Malaria: Amazon and Ethiopia

The following new articles have just been published in Malaria Journal


Population dynamics, structure and behaviour of Anopheles darlingi in a rural settlement in the Amazon rainforest of Acre, Brazil
Moutinho PR, Gil LH, Cruz RB, Ribolla PE Malaria Journal 2011, 10:174 (24 June 2011)

Background
Anopheles darlingi is the major vector of malaria in South America, and its behaviour and distribution has epidemiological importance to biomedical research. In Brazil, An. darlingi is found in the northern area of the Amazon basin, where 99.5% of the disease is reported.

Methods
The study area, known as Ramal do Granada, is a rural settlement inside the Amazon basin in the state of Acre. Population variations and density have been analysed by species behaviour, and molecular analysis has been measured by ND4 mitochondrial gene sequencing.

Results
The results show higher density in collections near a recent settlement, suggesting that a high level of colonization decreases the vector presence. The biting activity showed higher activity at twilight and major numbers of mosquitoes in the remaining hours of the night in months of high density. From a sample of 110 individual mosquitoes, 18 different haplotypes were presented with a diversity index of 0.895, which is higher than that found in other Anopheles studies.

Conclusions
Anopheles darlingi depends on forested regions for their larval and adult survival. In months with higher population density, the presence of mosquitoes persisted in the second part of the night, increasing the vector capacity of the species. Despite the intra-population variation in the transition to rainy season, the seasonal distribution of haplotypes shows no change in the structure population of An. darlingi.



Research
Urban malaria and associated risk factors in Jimma town, south-west Ethiopia Alemu A, Tsegaye W, Golassa L, Abebe G
Malaria Journal 2011, 10:173 (24 June 2011)

Background
Malaria kills millions around the world. Until recently it was believed to be a disease of rural areas, since the Anopheles mosquito, which transmits Plasmodium species breeds in rural areas. Urban malaria is emerging as a potential, but "avertable" crisis, in Africa. In view of the rapidly growing number of small and medium-sized towns in Ethiopia there is a pressing need to improve the understanding of the epidemiology of malaria. Therefore, the aim of this study was to determine malaria prevalence and associated risk factors in Jimma town.

Methods
A cross-sectional study was carried out in Jimma town from April 1 to May 28, 2010. 804 study participants were included from 291 households for microscopic examination of malaria parasites. Socio-demography data and risk factors were collected using structured questionnaires. Logistic regression analysis was done using SPSS 15.0 statistical software.

Results
From a total of 804 study participants in current survey only 42 (5.2%) were positive for malaria parasites. Plasmodium vivax, Plasmodium falciparum and mixed infection accounted 71.4%, 26.2% and 2.4%, respectively. Higher malaria prevalence rate was observed among under-five children (11%). Those who do not use insecticide-treated bed nets (ITN) were more likely to be infected with malaria (OR=13.6; 95% CI 4.9-37.2, p<0.001) compared with those who use the ITN. Living in areas where stagnant water existed (OR=2.1; 95% CI 1.00-4.2, p=0.047) and its distance of existence <1 km from the house(OR=2.1; 95% CI 2.0-15.8, p=0.001) were more likely to be infected with malaria parasite compared with those who live away from stagnant at a distance greater than 1 km.

Conclusion
Malaria is a major health problem with P. vivax becoming a predominant species in the town. The prevalence was strongly associated with proximity of residence to potential mosquito breeding sites. Malaria is affecting significant proportions of the urban settlers and human activities nevertheless play an important role in bringing the mosquito breeding sites closer to residences.

MALARIA: Can Southern Sudan Vote for Independence from Malaria?

Bill Brieger : 31 Dec 2010
The UNDP is also responsible for the Global Fund Round 7 Malaria Grant in Northern Sudan. It may be doing a better job with its malaria assignment. The most recent grant progress report rated them well with a ‘B1′, but raised the concern that, “The cash absorption rate during this reporting period is only 56% of the budget. This is attributed to delays in procurements.”
The North has a mix of malaria transmission situations, while the South is squarely in the endemic zone (as seen in map to right). When the South votes soon for Independence, what will be their own chances of becoming independent from malaria?
The Round 7 Malaria Grant in the South is managed by PSI. The Grant started 2 years ago and currently also rates a ‘B1′. At the most recent grant progress report dated October 2010, the following were achieved:
86% of ITNs had been distributed
10 BCC media campaigns had been implemented and over 6000 community organization staff had been trained, exceeding targets
Only 17% of targeted children had been treated with ACTs in the community
Health facilities exceeded expectations in terms of maintaining ACT stocks
The progress report concludes that, “Strengthening the capacity of the health system to deliver health services including malaria interventions have fallen behind set targets, due to late SR selection and contracting, and the PR focusing on the LLIN mass distribution campaign. Nevertheless, results seem to be gaining on set targets.”
Southern Sudan is not without malaria partners. For example, PSI has been working Southern Sudan since “January 2005, distributing Serena long-lasting insecticide-treated nets (LLIN) through the commercial sector … (and providing) support to the Ministry of Health (MOH), Government of Southern Sudan, and county health departments to prevent and treat malaria.” The IRC has trained “villagers to recognize and treat young children for malaria, diarrhea and pneumonia has helped to reduce child deaths by 81 percent in one area of Southern Sudan.”
USAID is also working to help tackle the malaria problem in Southern Sudan. The area has been one of three ‘non-focus’ countries - that is not formally under the US President’s Malaria Initiative (PMI). Two of these countries, Nigeria and Democratic Republic of the Congo, have been added to the formal PMI roster. One wonders whether the fate of malaria control in Southern Sudan rests on the election outcomes.
The BBC quotes a Southern Sudanese nurse who compares the upcoming referendum, “.. as a mother giving birth to twins - once the labour pains are over, the two children can grow up as friends .” We know that malaria during ‘pregnancy’ and during ‘infancy and young childhood’ are threats to survival. We hope that all donors will continue to work for the survival of these Sudanese ‘children’ and bring about a true independence from malaria.
http://www.malariafreefuture.org/blog/?p=1142

MALARIA: Changing malaria intervention coverage, transmission and hospitalization in Kenya.

EA Okiro, VA Alegana, AM Noor, and RW Snow
 October 15, 2010
 BACKGROUND:
Reports of declining incidence of malaria disease burden across several countries in Africa suggest that the epidemiology of malaria across the continent is in transition. Whether this transition is directly related to the scaling of intervention coverage remains a moot point.
METHODS:
Paediatric admission data from eight Kenyan hospitals and their catchments have been assembled across two three-year time periods: September 2003 to August 2006 (pre-scaled intervention) and September 2006 to August 2009 (post-scaled intervention). Interrupted time series (ITS) models were developed adjusting for variations in rainfall and hospital use by surrounding communities to show changes in malaria hospitalization over the two periods. The temporal changes in factors that might explain changes in disease incidence were examined sequentially for each hospital setting, compared between hospital settings and ranked according to plausible explanatory factors.
RESULTS:
In six out of eight sites there was a decline in Malaria admission rates with declines between 18% and 69%. At two sites malaria admissions rates increased by 55% and 35%. Results from the ITS models indicate that before scaled intervention in September 2006, there was a significant month-to-month decline in the mean malaria admission rates at four hospitals (trend P<0.05). At the point of scaled intervention, the estimated mean admission rates for malaria was significantly less at four sites compared to the pre-scaled period baseline. Following scaled intervention there was a significant change in the month-to-month trend in the mean malaria admission rates in some but not all of the sites. Plausibility assessment of possible drivers of change pre- versus post-scaled intervention showed inconsistent patterns however, allowing for the increase in rainfall in the second period, there is a suggestion that starting transmission intensity and the scale of change in ITN coverage might explain some but not all of the variation in effect size. At most sites where declines between observation periods were documented admission rates were changing before free mass ITN distribution and prior to the implementation of ACT across Kenya.
CONCLUSION:
This study provides evidence of significant within and between location heterogeneity in temporal trends of malaria disease burden. Plausible drivers for changing disease incidence suggest a complex combination of mechanisms, not easily measured retrospectively.
http://malariajournal.com/content/9/1/285

MALARIA: Potential threat of malaria epidemics in a low transmission area

Malaria Journal 2010, 9:264doi:10.1186/1475-2875-9-264
 29 September 2010
Abstract (provisional)
Background
Plasmodium falciparum is the major cause of malaria infection in the island of Sao Tome, in the Republic of Sao Tome and Principe (STP), with an incidence of 40 - 50% before 2004. Since 2004, through the coordination of the Ministry of Health of STP and their Centro Nacional de Endemias (CNE), an integrated malaria control programme has been intensively deployed on the island of Sao Tome. Malaria morbidity and mortality decreased by 95% after three years of effective intervention. In the low transmission settings, however, malaria seasonal fluctuation can be a potential problem directly related to epidemics if ongoing control measures are interrupted. Studies on a number of associated factors with malaria epidemics and the measures taken to respond to outbreaks are presented.
Methods
The integrated malaria control programme included indoor residual spraying (IRS), long-lasting insecticidal nets (LLINs), intermittent preventive therapy for pregnant women, as well as early diagnosis and prompt treatment with artemisinin-based combination therapy (ACT). Regular implementation of an island-wide IRS programme was carried out yearly in 2004-2007, and enhanced throughout the island in 2009. Malaria incidence and prevalence were estimated based on passive case detection and mass screening, respectively. Slide positivity rates were used for monitoring the beginning of a malaria epidemic or a seasonal peak.
Results
A steep decline of ca. 95% of malaria morbidity and mortality was observed between 2004 and 2008 with use of the combined control methods. Malaria incidence was 2.0%, 1.5%, and 3.0% for 2007, 2008, and 2009, respectively. In April 2008, a cross-sectional country-wide surveillance showed malaria prevalence of 3.5%, of which 95% cases were asymptomatic carriers. Only 50% of asymptomatic carriers were cured with ACT treatment, while 90% of the symptomatic patients were cured by ACT treatment as confirmed with a follow up study. Malaria morbidity increased by three-fold during the first half of 2009 as compared to the same period in 2008. Over this period of six months, severe malaria was also noted in all age groups and malaria mortality increased by two-fold in children less than five years old. After an emergency IRS was deployed, with increased use of LLINs, and an active search of asymptomatic carriers was followed and given complete ACT treatment, malaria incidence decreased to less than 1% in the second half of 2009.
Conclusion
At the initial stage of the integrated malaria control programme, IRS contributed to the visible effect on the rapid reduction of malaria morbidity and mortality, while this programme highlights an urgent demand for the improvement of other measures, particularly promotion of LLINs usage, with close monitoring of asymptomatic carriers and with ACT treatment in malaria transmission hotspots. In addition, both daily reports and a regular active surveillance to prevent malaria outbreaks should be established permanently, so that a fast response to epidemics can be effectively made when necessary.
http://www.malariajournal.com/content/9/1/264

POVERTY & MALARIA: Poverty and fever vulnerability in Nigeria: a multilevel analysis

Background
Malaria remains a major public health problem in Sub Saharan Africa, where widespread poverty also contribute to the burden of the disease. This study was designed to investigate the relationship between the prevalence of childhood fever and socioeconomic factors including poverty in Nigeria, and to examine these effects at the regional levels.
Methods
Determinants of fever in the last two weeks among children under five years were examined from the 25004 children records extracted from the Nigeria Demographic and Health Survey 2008 data set. A two-level random effects logistic model was fitted.
Results
About 16% of children reported having fever in the two weeks preceding the survey. The prevalence of fever was highest among children from the poorest households (17%), compared to 15.8% among the middle households and lowest among the wealthiest (13%) (p<0.0001). p="0.082)." or="1.27," or="0.92," p="0.022,">6months), whereas the effect of wealth no longer reached statistical significance.
Conclusion
While, overall bednet possession was low, less fever was reported in households that possessed bednets. Malaria control strategies and interventions should be designed that will target the poor and make an impact on poverty. The mechanism through which wealth may affect malaria occurrence needs further investigation.
http://www.malariajournal.com/content/9/1/235

MALARIA: P vivax malaria is greater threat to health than thought

A new study of the prevalence of the malaria parasite Plasmodium vivax shows that it is more widespread and potentially represents a greater burden on human health in some parts of the world than P falciparum, the species usually associated with the greatest mortality and morbidity.
A new evidence based global distribution map of P vivax estimates that 2.85 billion people lived at risk of infection with this parasite in 2009, predominantly in east and central Asia (PLoS Neglected Tropical Diseases, doi:10.1371/journal.pntd.0000774).
The study, conducted as part of the Malaria Atlas Project, a multinational research collaboration funded mainly by the Wellcome Trust, challenges the idea that P vivax transmission doesn’t occur in large swathes of Africa. It used novel methods, including developing new global maps of Duffy negativity, which confers partial protection against P vivax. People who are Duffy negative lack an antigen on the surface of red blood cells that codes for a protein receptor for P vivax.
"This study represents the first step in our efforts to provide the malaria control and research community with an evidence based cartography of P vivax malaria," said one of the coauthors, Simon Hay, reader in infectious disease epidemiology at the University of Oxford. "We can now focus on trying to model the endemicity of the disease to provide more detailed global burden estimates, although this is complicated by the unusual biology of P vivax."
Another coauthor, Carlos Guerra, who is responsible for the design, construction, and maintenance of the Malaria Atlas Project database at Oxford University’s Spatial Ecology and Epidemiology Group, said, "New evidence shows that P vivax malaria is not as benign as was thought and yet, as our study shows, remains the most widespread form of human malaria. Understanding where transmission of this parasite occurs at the global scale is fundamental in planning strategies for the control of this debilitating and sometimes lethal disease."
Dr Guerra explained: "Recent studies from areas where both P vivax and P falciparum are endemic have used advanced diagnostic techniques to confirm that some of the severe complications of malarial infection traditionally attributed to P falciparum are also related to P vivax infection.
"The classical notion that ‘benign malaria’ is a synonym of P vivax infection is being challenged by these new findings."
Globally P falciparum "is undeniably the main killer" of the two, Dr Guerra said. Even though worldwide more people are exposed to risk of P vivax infection than P falciparum, most deaths from malaria are reported in Africa, "where P vivax infection is rather uncommon due to the high prevalence of Duffy negativity in large parts of the continent," he added.
Outside Africa, however, where P vivax transmission is common and causes about half of the reported cases of malaria, observed fatality rates associated with the two species are similar, although more studies are needed to determine which parasite actually causes more morbidity and mortality in these settings, Dr Guerra said.
Although more attention has traditionally been paid to combating P falciparum, the new findings show that P vivax shouldn’t be overlooked in the global campaign against malaria, he concluded.
Further information about the Malaria Atlas Project can be found at www.map.ox.ac.uk.
http://www.bmj.com/cgi/content/full/341/aug03_1/c4188

MALARIA: Kenya: Stable and Unstable Malaria Hotspots in Longitudinal Cohort Studies in Kenya

Background
Infectious diseases often demonstrate heterogeneity of transmission among host populations. This heterogeneity reduces the efficacy of control strategies, but also implies that focusing control strategies on “hotspots” of transmission could be highly effective.
Methods and Findings
In order to identify hotspots of malaria transmission, we analysed longitudinal data on febrile malaria episodes, asymptomatic parasitaemia, and antibody titres over 12 y from 256 homesteads in three study areas in Kilifi District on the Kenyan coast. We examined heterogeneity by homestead, and identified groups of homesteads that formed hotspots using a spatial scan statistic. Two types of statistically significant hotspots were detected; stable hotspots of asymptomatic parasitaemia and unstable hotspots of febrile malaria. The stable hotspots were associated with higher average AMA-1 antibody titres than the unstable clusters (optical density [OD] = 1.24, 95% confidence interval [CI] 1.02–1.47 versus OD = 1.1, 95% CI 0.88–1.33) and lower mean ages of febrile malaria episodes (5.8 y, 95% CI 5.6–6.0 versus 5.91 y, 95% CI 5.7–6.1). A falling gradient of febrile malaria incidence was identified in the penumbrae of both hotspots. Hotspots were associated with AMA-1 titres, but not seroconversion rates. In order to target control measures, homesteads at risk of febrile malaria could be predicted by identifying the 20% of homesteads that experienced an episode of febrile malaria during one month in the dry season. That 20% subsequently experienced 65% of all febrile malaria episodes during the following year. A definition based on remote sensing data was 81% sensitive and 63% specific for the stable hotspots of asymptomatic malaria.
Conclusions
Hotspots of asymptomatic parasitaemia are stable over time, but hotspots of febrile malaria are unstable. This finding may be because immunity offsets the high rate of febrile malaria that might otherwise result in stable hotspots, whereas unstable hotspots necessarily affect a population with less prior exposure to malaria.
When transmission has reduced to very low levels, transmission remains geographically clustered [9,79], and intensified control in these hotspots is key to achieving elimination. In our setting, as inmuch of sub-Saharan Africa, there is not an immediate prospect of elimination. Additional targeted control measures may be viewed simply as a cost-effective way of ensuring that those most in needget the intervention, but the stronger justification is that reducing transmission in hotspots will reduce transmission on the wider community [1].Environmental interactions are complex in determining malaria risk per se [12], and so these findings should be validated in other datasets before firm recommendations for malaria controlprogrammes are made.
Editors' Summary
Background
Malaria, a mosquito-borne parasitic disease, is a major global public-health problem. About half the world's population is at risk of malaria and about one million people (mainly children living in sub-Saharan Africa) die each year from the disease. Malaria is transmitted to people through the bite of an infected mosquito. Initially, the parasite replicates inside human liver cells but, about a week after infection, these cells release “merozoites” (one of the life-stages of the parasite), which invade red blood cells. Here, the merozoites replicate rapidly before bursting out after 2–3 days and infecting more red blood cells. The cyclical and massive increase in parasitemia (parasites in the bloodstream) that results from this pattern of replication is responsible for malaria's recurring fevers and can cause life-threatening organ damage and anemia (a lack of red blood cells). Malaria can be prevented by controlling the mosquitoes that spread the parasite and by avoiding mosquito bites. Effective treatment with antimalarial drugs can also reduce malaria transmission.
Why Was This Study Done?
Like many other infectious diseases, the transmission of malaria is heterogeneous. That is, even in places where malaria is always present, there are “hotspots” of transmission, areas where the risk of catching malaria is particularly high. The existence of these hotspots, which are caused by a combination of genetic factors (for example, host susceptibility to infection) and environmental factors (for example, distance from mosquito breeding sites), reduces the efficacy of control strategies. However, mathematical models suggest that focusing control strategies on transmission hotspots might be an effective way to reduce overall malaria transmission. Efforts have been made to identify such hotspots using environmental data collected by satellites but with limited success. In this study, therefore, the researchers investigate the heterogeneity of malaria transmission in the Kilifi District of Kenya over time by analyzing data collected over up to 12 years (“longitudinal” data) on malaria episodes and parasitemia in three groups (cohorts) of children living in 256 homesteads.
What Did the Researchers Do and Find?
The researchers identified febrile malaria episodes in the homesteads by taking blood from children with fever (febrile children) to analyze for parasitemia. They took blood once a year from all the study participants just before the rainy season (when malaria peaks) to look for symptom-free parasitemia and they also looked for antibodies (proteins made by the immune system that fight disease) against malaria parasites in the blood of the participants. They then used a “spatial scan statistic” to look for heterogeneity of transmission and to identify transmission hotspots (groups of homesteads where the observed incidence of malaria or parasitemia was higher than would be expected if cases were evenly distributed). The researchers identified two types of hotspots—stable hotspots of symptom-free parasitemia that were still hotspots several years later and unstable hotspots of febrile malaria that rarely stayed in the same place for more than a year or two. Children living in the stable hotspots had slightly higher average amounts of antimalaria antibodies and developed malaria at a slightly lower average age than children living in the unstable hotspots.
What Do These Findings Mean?
These findings show that in Kilifi District, Kenya, hotspots of symptom-free parasitemia are stable over time but hotspots of febrile malaria are unstable. The researchers suggest that rapid acquisition of immunity in the stable hotspots reduces the occurrence of febrile malaria whereas in the unstable hotspots there is a high incidence of febrile malaria because lack of previous exposure to the parasite means there is a low level of immunity. Targeted strategies for malaria control should target both types of hotspots, suggest the researchers. Stable hotspots of symptom-free parasitemia (which can be identified by parasite or antibody surveys or by remote environmental sensing) should be targeted because mosquito dispersion probably increases malaria transmission rates near these hotspots. Unstable hotspots of febrile disease should be targeted to reduce both the burden of disease and transmission in the wider community. Unstable hotspots of febrile malaria, the researchers suggest, could be efficiently identified in Kilifi District (and maybe elsewhere) by determining which homesteads had malaria outbreaks during September (part of the dry season) one year and then focusing control interventions on these homesteads the next year.
http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000304

MALARIA: Uganda fails to reduce malaria by 50%

27th July, 2010
UGANDA has performed poorly in the fight against malaria due to the suspension of funding by the Global Fund in 2005 over massive corruption. As a result, Uganda is not among the countries in Africa that have reduced malaria infections and deaths by 50% as it was envisaged. Countries that have reduced morbidity and mortality by 50% include Rwanda, Tanzania, Zanzibar, Eritrea, Botswana, Cape Verde, Namibia, South Africa, Zambia, Swaziland, São Tomé and Príncipe. The nations were expected to achieve universal distribution of insecticide-treated mosquito bed-nets, increase anti-malarial distribution and treatment and spraying to control mosquitoes that transmit the malaria parasite.
http://www.newvision.coug/D/8/13/727097

MALARIA: Phillipines epidemic

Department of Health in Bicol has declared a malaria epidemic in Camarines Norte. Reports say that 182 people have been stricken by the mosquito borne parasitic disease.
Most cases have occurred in the town of Jose Panganiban, however in an effort to prevent the spread of disease, the entire province has been declared an epidemic.
DOH officials report that the majority of victims of malaria were children and the elderly. Approximately 20 percent of those infected were members of a tribal community.
The report did not specify what type of malaria is the cause of the epidemic.
http://www.examiner.com/x-7707-Infectious-Disease-Examiner~y2010m7d27-Malaria-epidemic-in-the-Bicol-Region-of-the-Philippines

MALARIA: progressive declining in the burden of malaria in north-eastern Tanzania

23 July 2010
Abstract (provisional)
Background
The planning and assessment of malaria interventions is complicated due to fluctuations in the burden of malaria over time. Recently, it has been reported that the burden of malaria in some parts of Africa has declined. However, community-based longitudinal data are sparse and the reasons for the apparent decline are not well understood.
Methods
Malaria prevalence and morbidity have been monitored in two villages in north-eastern Tanzania; a lowland village and a highland village from 2003 to 2008. Trained village health workers treated presumptive malaria with the Tanzanian first-line anti-malarial drug and collected blood smears that were examined later. The prevalence of malaria parasitaemia across years was monitored through cross-sectional surveys.
Results
The prevalence of malaria parasitaemia in the lowland village decreased from 78.4 % in 2003 to 13.0 % in 2008, whereas in the highland village, the prevalence of parasitaemia dropped from 24.7% to 3.1% in the same period. Similarly, the incidence of febrile malaria episodes in the two villages dropped by almost 85% during the same period and there was a marked reduction in the number of young children who suffered from anaemia in the lowland village.
Conclusion
There has been a marked decline in malaria in the study villages during the past few years. This decline is likely to be due to a combination of factors that include improved access to malaria treatment provided by the trained village helpers, protection from mosquitoes by increased availability of insecticide-impregnated bed nets and a reduced vector density. If this decline in malaria morbidity is sustained, it will have a marked effect on the disease burden in this part of Tanzania.
http://www.malariajournal.com/content/9/1/216

MALARIA: An evaluation of historical and current definitions of malaria elimination

22 July 2010
Abstract (provisional)
Decisions to eliminate malaria from all or part of a country involve a complex set of factors, and this complexity is compounded by ambiguity surrounding some of the key terminology, most notably "control" and "elimination." It is impossible to forecast resource and operational requirements accurately if endpoints have not been defined clearly, yet even during the Global Malaria Eradication Program, debate raged over the precise definition of "eradication." Analogous deliberations regarding the meaning of "elimination" and "control" are basically nonexistent today despite these terms' core importance to programme planning. To advance the contemporary debate about these issues, this paper presents a historical review of commonly used terms, including control, elimination, and eradication, to help contextualize current understanding of these concepts. The review has been supported by analysis of the underlying mathematical concepts on which these definitions are based through simple branching process models that describe the proliferation of malaria cases following importation. Through this analysis, the importance of pragmatic definitions that are useful for providing malaria control and elimination programmes with a practical set of strategic milestones is emphasized, and it is argued that current conceptions of elimination in particular fail to achieve these requirements. To provide all countries with precise targets, new conceptual definitions are suggested to more precisely describe the old goals of "control" - here more exactly named "controlled low-endemic malaria" - and "elimination." Additionally, it is argued that a third state, called "controlled non-endemic malaria," is required to describe the epidemiological condition in which endemic transmission has been interrupted, but malaria resulting from onwards transmission from imported infections continues to occur at a sufficiently high level that elimination has not been achieved. Finally, guidelines are discussed for deriving the separate operational definitions and metrics that will be required to make these concepts relevant, measurable, and achievable for a particular environment.
http://www.malariajournal.com/content/9/1/213

MALARIA: Amazon tree cutting increases malaria incidence

MADISON — Establishing a firm link between environmental change and human disease has always been an iffy proposition.
Now, however, a team of scientists from the University of Wisconsin-Madison, writing in the current (June 16, 2010) online issue of the CDC journal Emerging Infectious Diseases, presents the most enumerated case to date linking increased incidence of malaria to land-use practices in the Amazon.
The report, which combines detailed information on the incidence of malaria in 54 Brazilian health districts and high-resolution satellite imagery of the extent of logging in the Amazon forest, shows that clearing tropical forest landscapes boosts the incidence of malaria by nearly 50 percent.
"It appears that deforestation is one of the initial ecological factors that can trigger a malaria epidemic," says Sarah Olson, the lead author of the new report and a postdoctoral fellow at the Nelson Institute, Center for Sustainability and the Global Environment.
The clearing of tropical forests, say Olson and senior author Jonathan Patz of the University of Wisconsin School of Medicine and Public Health, creates conditions that favor malaria's primary carrier in the Amazon, the mosquito Anopheles darlingi, which transmits the malaria parasite if it draws its blood meals from infected humans.
"The deforested landscape, with more open spaces and partially sunlit pools of water, appears to provide ideal habitat for this mosquito," Olson says, noting that Anopheles darlingi has been shown to displace other types of mosquitoes that prefer forest and that are far less prone to transmit malaria.
"This study of human malaria cases complements our previous work that focused more on the abundance of the malaria-carrying mosquito," Patz adds. "In those studies from the Peruvian Amazon, we showed a correlation between this mosquito's larvae and aquatic breeding sites in disturbed habitats following land clearance."
The new Wisconsin study focused on 54 Brazilian health districts in a corner of the Brazilian Amazon near Peru and where detailed health and population data were collected in 2006 by Brazilian researchers. Combined with high-resolution satellite data of changes in land cover, the health data reveals the large human-health impact of relatively small changes to the forest landscape.
"A 4 percent change in forest cover was associated with a 48 percent increase in malaria incidence in these 54 health districts," notes Olson. "The health data used in the study is of the highest quality and spatial resolution. Unlike previous studies, our data allowed us to zoom in on areas where people are being exposed to malaria and to exclude areas where they are not being exposed."
The health districts reflected in the Wisconsin study are typical of many of the thousands of such districts spread across Brazil and its Amazon region. Since 2001, the Brazilian Ministry of Health has similarly monitored and treated malaria in more than 7,000 districts. Deforestation in the districts, says Olson, is occurring as it typically does in Amazonia, and occurs mostly near rivers, the backbone of the region's transportation system, and spreads outward.
The new work, argues Patz, an authority on environmental change and human health, shows how deforestation and land clearing contribute to malaria's dynamic at the frontier of settlement. "In 2006, the county that encompasses these health districts was in the top five of all Brazilian counties with malaria," Patz says. "Even after we adjusted for human populations, access to healthcare and other factors, malaria hotspots paralleled locations with the most destruction of rainforests."
The message from the study, say Olson and Patz, is that tropical forest conservation may benefit human health more than we realized.
"Land-management practices show promise as useful interventions to reduce malaria risk factors," says Olson.
Patz and Olson believe the new work provides a template that could be used to spatially track environmental risk factors and the incidence of malaria, which infected an estimated 500,000 Brazilians annually across the Amazon basin from 1997 to 2006. "The technology is there. The health data is there. Health officers with cell phones could gather data for the whole Amazon region," Olson says.
http://www.sciencecodex.com/incidence_of_malaria_jumps_when_amazon_forests_are_cut

MALARIA: Estimating the Global Clinical Burden of Plasmodium falciparum Malaria in 2007

Background
The epidemiology of malaria makes surveillance-based methods of estimating its disease burden problematic. Cartographic approaches have provided alternative malaria burden estimates, but there remains widespread misunderstanding about their derivation and fidelity. The aims of this study are to present a new cartographic technique and its application for deriving global clinical burden estimates of Plasmodium falciparum malaria for 2007, and to compare these estimates and their likely precision with those derived under existing surveillance-based approaches.
Methods and Findings
In seven of the 87 countries endemic for P. falciparum malaria, the health reporting infrastructure was deemed sufficiently rigorous for case reports to be used verbatim. In the remaining countries, the mapped extent of unstable and stable P. falciparum malaria transmission was first determined. Estimates of the plausible incidence range of clinical cases were then calculated within the spatial limits of unstable transmission. A modelled relationship between clinical incidence and prevalence was used, together with new maps of P. falciparum malaria endemicity, to estimate incidence in areas of stable transmission, and geostatistical joint simulation was used to quantify uncertainty in these estimates at national, regional, and global scales.
Combining these estimates for all areas of transmission risk resulted in 451 million (95% credible interval 349–552 million) clinical cases of P. falciparum malaria in 2007. Almost all of this burden of morbidity occurred in areas of stable transmission. More than half of all estimated P. falciparum clinical cases and associated uncertainty occurred in India, Nigeria, the Democratic Republic of the Congo (DRC), and Myanmar (Burma), where 1.405 billion people are at risk.
Recent surveillance-based methods of burden estimation were then reviewed and discrepancies in national estimates explored. When these cartographically derived national estimates were ranked according to their relative uncertainty and replaced by surveillance-based estimates in the least certain half, 98% of the global clinical burden continued to be estimated by cartographic techniques.
Conclusions and Significance
Cartographic approaches to burden estimation provide a globally consistent measure of malaria morbidity of known fidelity, and they represent the only plausible method in those malaria-endemic countries with nonfunctional national surveillance. Unacceptable uncertainty in the clinical burden of malaria in only four countries confounds our ability to evaluate needs and monitor progress toward international targets for malaria control at the global scale. National prevalence surveys in each nation would reduce this uncertainty profoundly. Opportunities for further reducing uncertainty in clinical burden estimates by hybridizing alternative burden estimation procedures are also evaluated.
http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000290

MALARIA: MDG's

MDGs are eight time-bound goals tackling poverty and its various dimensions that member states of the United Nations and other international organisations have agreed to meet by 2015. "We either win this fight or we lose it. There can be no let-up in the fight against the three diseases," said U.N. secretary-general Ban Ki- moon in a message last month, as he described the progress made by the Global Fund, which has been the main contributor to the health-related MDGs. Professor Kevin Marsh, director of the Kenya Medical Research Institute Wellcome Trust programme in Kilifi, Kenya, cites the experience of Africa to stress the impact of efforts to fight one of the world’s killer diseases on meeting the MDGs. "In Africa, if you control malaria, you can reduce childhood mortality down to the levels to achieve MDGs," he says. In coastal Kenya, for instance, malaria has dropped by 90 percent in the last five years and infant childhood deaths have dropped from 115 deaths per 1,000 under-five children to 74 last year, he recounts. Malaria causes 500 million episodes of illness, almost 40 percent of them in Asia, and one million deaths annually, 90 per cent of them in Africa, says WHO. "The changing epidemiology of malaria in Southeast Asia, including the emergence and spread of drug-resistant strains of the parasite, are posing fresh challenges to regional elimination efforts," says Professor Ric Price of the Menzies School of Health research in Darwin. "To achieve the ultimate goal of malaria control, we estimate that four to five billion U.S. dollars are needed per year, sustained over the next 20 to 30 years." Parts of South-east Asia are already witnessing the emergence of malarial strains that are resistant to ‘artemesinins’, drugs the world depends on to treat malaria. If such a situation is not controlled, "it will be a very serious global health issue," warns Marsh, who is also a professor of Tropical Medicine at Oxford University. There are five species of malaria that commonly infect humans, two of which pose the greatest health risks –‘Plasmodium falciparum’ and ‘P. vivax’ to humans. In Asia, the challenge lies in controlling the ‘P. vivax’ malaria. The emergence of another species of potentially fatal adult malaria, ‘Plasmodium knowlesi’, has also been noted in the region, particularly in Malaysia. Pig-tailed and long-tailed macaques monkeys are the reservoirs of this parasite, says Timothy William, head of the Infectious Disease Unit at Queen Elizabeth Hospital in Sabah, Malaysia. "It is difficult to treat or eradicate the reservoirs for obvious reasons. In our study, about 30 percent of the cases presented with severe disease. Therefore it is imperative that these cases are diagnosed early and treated," he says. Research has shown that more than 60 percent of emerging infectious diseases have been related to animal and human contact. "Of these, 70 percent are due to contact between humans and wildlife. In developing countries, these issues are even more important with increasing land clearing, intensive farming of poultry, and infections passing from wild birds into domestic birds," Sorrell tells IPS. Still another major challenge to the global health community is the growing drug resistance of certain diseases, particularly to antibiotics. These include tuberculosis, typhoid, malaria, and sexually transmitted diseases like gonorrhoea. In recent years, there has been a renewed commitment to vaccine research to prevent and treat these infections and other preventable diseases in the developing world. "The issue in the long term is affording the vaccines in routine use," says Marsh, who adds that immunisation has been "one of the most successful international efforts to curb the spread of diseases." Immunisation is particularly crucial for children at risk for pneumococcal disease, says Dr Andrew Pollard, professor of paediatric infection and immunity and director of the Oxford Vaccine Group at Oxford University. "Streptococcus pneumoniae is the leading cause of pneumonia in childhood and kills more children in South Asia and South East Asia than any other disease," he says.
http://www.ipsnews.net/news.asp?idnews=51795

MALARIA: PROTECTIVE EFFICACY OF INTERVENTIONS FOR PREVENTING MALARIA MORTALITY IN CHILDREN IN PLASMODIUM FALCIPARUM ENDEMIC AREAS

We estimate the protective efficacy of insecticide-treated mosquito nets and indoor-residual spraying on reducing malaria-attributable mortality 1–59 months to be 55%, with a range of 49–61%, in Plasmodium falciparum settings.
We estimate malaria prevention interventions in pregnancy (intermittent preventive therapy and insecticide-treated mosquito nets) to have a pooled protective efficacy of 35% (95% confidence interval: 23–45%) on reducing the prevalence of low birth weight in the first or second pregnancy in areas of stable Plasmodium falciparum transmission.
These data support the continued scale-up of these malaria prevention interventions in endemic settings that will prevent a considerable number of child deaths due directly and indirectly to malaria.
These protective efficacy estimates will allow the use of the LiST model for estimating the likely impact of past intervention scale-up, as well as for predicating future impact of intervention scale-up by national malaria control programs.
http://ije.oxfordjournals.org/cgi/content/full/39/suppl_1/i88?view=long&pmid=20348132

MALARIA: Health metrics assessment

It is clear that most countries will not reach the Millennium Development Goal targets by 2015. Yet there can still be dramatic improvements over the next five years – and beyond – if we take the opportunity to learn from the successes and find ways to replicate them.
In an era where demonstrating the effectiveness of development assistance for health is becoming increasingly important, following up this study with careful country case studies will be vital. Bursts of rapid improvement are possible, with countries such as Egypt and Tunisia achieving remarkable declines in both maternal and child mortality rates.
Country-specific research that focuses on the steps taken to achieve these rapid reductions could reveal the necessary formula for countries that are falling behind. We also need to know more about how interventions targeted at child and maternal health are working. To better understand child mortality reductions, we must examine how policy initiatives such as vaccine programs, insecticide-treated bed net distribution, or the scale-up of antiretroviral treatment
are contributing to accelerated mortality declines.
Next steps could include exploring how levels and trends in child mortality are related to changes in the key drivers of child mortality, including income per capita, levels of maternal education, the HIV epidemic, and malaria. Studying these indicators will help us understand where country performance has been better than expected.
With hindsight, we can ask whether the targets set for MDG4 and MDG5 were realistic or overly ambitious. Looking past 2015, when a new round of health targets may be formulated, it will be important to ground the choice of targets in an informed discussion of the distribution of progress across nations.
http://www.healthmetricsandevaluation.org/print/reports/2010/building/building_momentum_conclusion_IHME_0610.pdf

MALARIA: Use of bed nets -- populations compared

Insecticide-treated nets (ITNs) are becoming increasingly available to vulnerable populations at risk for malaria. Their appropriate and consistent use is essential to preventing malaria, but ITN use often lags behind ITN ownership. In order to increase ITN use, it is necessary to devise strategies that accurately identify, differentiate, and target the reasons and types of non-use.
Methods
A simple method based on the end-user as the denominator was employed to classify each individual into one of four ITN use categories: 1) living in households not owning an ITN; 2) living in households owning, but not hanging an ITN; 3) living in households owning and hanging an ITN, but who are not sleeping under one; and 4) sleeping under an ITN. This framework was applied to survey data designed to evaluate long-lasting insecticidal nets (LLINs) distributions following integrated campaigns in five countries: Togo, Sierra Leone, Madagascar, Kenya and Niger.
Results
The percentage of children <5 years of age sleeping under an ITN ranged from 51.5% in Kenya to 81.1% in Madagascar. Among the three categories of non-use, children living in households without an ITN make up largest group (range: 9.4%-30.0%), despite the efforts of the integrated child health campaigns. The percentage of children who live in households that own but do not hang an ITN ranged from 5.1% to 16.1%. The percentage of children living in households where an ITN was suspended, but who were not sleeping under it ranged from 4.3% to 16.4%. Use by all household members in Sierra Leone (39.9%) and Madagascar (60.4%) indicate that integrated campaigns reach beyond their desired target populations.
Conclusions
The framework outlined in this paper provides a helpful tool to examine the deficiencies in ITN use. Monitoring and evaluation strategies designed to assess ITN ownership and use can easily incorporate this approach using existing data collection instruments that measure the standard indicators.
http://www.malariajournal.com/content/9/1/133

MALARIA: Venezuela outbreak among gold miners

CARACAS, Venezuela (AP) - Malaria cases have doubled in Venezuela so far this year as health officials confront an epidemic in a vast southern region where wildcat gold miners are often infected in remote jungle camps.
Health Ministry statistics published this week show there have been 21,601 malaria cases nationwide so far this year, up from 10,758 during the same period last year.
A vast majority of the patients - 19,750 - were diagnosed in southern Bolivar state, where government officials say there is an epidemic. The statistics, which are updated weekly and circulated among some health officials, cover the period running from the start of the year through May 22.
Miners in search of gold and diamonds have long caught the disease by venturing into forests where malaria-carrying mosquitoes live. Their strip-mines destroy patches of forest, leaving behind muddy pools and water contaminated with the mercury they use to separate gold from rock.
Public health officials attribute the rise in malaria cases in part to a government-led operation this year in which soldiers have evicted thousands of miners from their illegal strip-mines.
That has led to a movement of displaced miners to other towns, and they have carried the disease with them and helped it spread into areas that didn't used to have much malaria, said Dr. Ana Gineth Morales, who heads the Bolivar state Public Health Institute.
"We expected it. It hasn't taken us by surprise," Morales said in a telephone interview Friday, saying her agency had been fully prepared.
"We've been efficient in diagnosing, detecting," she said, adding that officials have largely managed to avoid deaths this year _ except for a single man in Bolivar, an elderly miner who died in January from malaria and complications from other health problems. Last year, she said, one Brazilian woman died of malaria in the state.
Morales said there has been an epidemic in parts of Bolivar since February. She expressed confidence that cases should eventually decline sharply as the government continues to root out illegal miners through its "Plan Caura" operation. But some critics say the malaria situation appears to be out of control. "We expect malaria cases will keep increasing," said Dr. Angel Granados, of the Bolivar state Medical Association. He said there are various factors contributing to the rise, including recent rains and movement of miners - but also "failures in control and prevention" measures by state health officials.
Public health teams haven't been reaching many remote areas including indigenous communities to detect and treat cases, Granados said.
Bolivar state has long been the epicenter for malaria in Venezuela, and the disease has been on the rise for the past few years. The country is on track this year to surpass the 2009 nationwide total of 35,725 cases - which also was an increase from 31,719 cases in 2008, according to Health Ministry figures.
Granados said there have recently been problems trying to supply medications to so many patients. "It worries all of us in the hospitals," he said.
Granados said one Yekuana Indian community earlier this year reported six deaths - including three children and three adults _ that came after they suffered high fevers and appeared to be due to malaria. But he said state health officials ruled out malaria saying the deaths were due to other causes and did not include them in their tally.
http://thestar.com.my/news/story.asp?file=/2010/6/5/apworld/20100605091049&sec=apworld

MALARIA: congenital malaria

BACKGROUND:
Congenital malaria has been increasingly documented in endemic regions. It is important to recognize those clinical features that are due to congenital malaria, which if undetected, might worsen the morbidity of the newborn. The aim of this study was to document the clinical presentation of neonates with congenital malaria born at the Lagos University Teaching Hospital and followed up for 28 days.
METHODS: A total of 100 consecutive mothers and their newborns were recruited between August and October 2002 (during the rainy season) from the labour ward and followed up from birth to 28 days of age. Blood films from the placentae and babies were stained with Giemsa stain within 24 hours of collection. All parasitaemic babies that became symptomatic were screened for sepsis using acute phase responses and cultures. All data were entered into a prepared proforma. Symptoms were attributed to malaria when sepsis screening was negative.
RESULTS: Congenital malaria was documented in 13.6% of babies at delivery. Jaundice, irritability and poor feeding were most common symptoms associated with congenital malaria. Irritability and poor feeding had positive predictive values (PPV) of 100% on Day 14.
CONCLUSION: Babies who present with poor feeding and irritability on Day 14 of life should be screened for malaria in addition to the routine investigations for neonatal sepsis.
http://www.ncbi.nlm.nih.gov/pubmed/20499743?dopt=Abstract

MALARIA: Learning to Count

World Malaria Day for both 2009 and 2010 had the theme ‘Counting Malaria Out’.1 The Abuja Declaration of 2000 set malaria control targets for 2010 that countries are trying to achieve by 31 December 2010, hoping that 80% of vulnerable groups (pregnant women, children under 5 years of age) would sleep under insecticide-treated nets (ITNs), that 80% of children under 5 would receive prompt and appropriate antimalarial treatment with artemisinin-based combination therapy (ACT), and that 80% of pregnant women would receive two doses of intermittent preventive treatment (IPTp).2
Before we can report whether these targets have been achieved we need to be able to count or document that these malaria control services have actually been delivered. As noted in the Lancet, ‘Without reliable information, government officials who allocate resources for health budgets in such countries are essentially working in the dark. The low quality of statistics results in adverse outcomes, such as underfunding and poor monitoring of many development programmes.’
http://www.africa-health.com/articles/may_2010/Malaria_06.pdf