Category Archives: Malaria

Malaria research during 2011

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The Ethiopian Malaria Prediction System (EMaPS) combines information about weather and water with demographic data to predict mosquito development and malaria risk.

Climate variability and changes may influence socio-economic development in Africa by affecting human health through extreme weather events and by bringing about changes in the ecology of infectious diseases. Malaria is a major climate sensitive public health problem in Ethiopia. Unfortunately, there are no practical tools for predicting malaria epidemics based on weather and climate information. Such tools would be useful in making a more efficient use of the limited resources for malaria control.

The project is a collaborative multidisciplinary research project. Researchers from Ethiopia and Norway work together to develop and validate models for predicting malaria transmission and set up an early warning by combining information on climate, water, epidemiological and entomological data. By the end of the project period, EMaPS will try to provide an implementation approach for early malaria warning. The project also aims to strengthen research, and improve interdisciplinary research capacity in Ethiopia and Norway.

The project contains several disciplines (see figure).

The project combined new population-based malaria transmission data with climate and land use variability data to develop early warning to predict malaria epidemics in Ethiopia. Such information is useful for the public and public institutions about the risk of malaria transmission and thus prevents malaria-related deaths.

Overall, eight PhD candidates (six Ethiopians and two Norwegians) take part in the project. The NUFU project funds four of these students, and four are funded by the University of Bergen. They collaborate and share data between the project parts.

We completed the data collection in 2010. During 2011, we mainly focused on data analysis, write-up and publication of the study findings. We expect all PhD candidates to defend their PhD thesis in 2012, and their works are briefly described below.

Abebe Animut is studying malaria mosquitoes in the highlands. He has described the occurrence of Anopheles arabiensis at altitudes as high as 2200m. He has also described the risk of malaria transmission at varying altitudes between 1700 and 2200 m altitude. His study provides good evidence that malaria transmission often occurs in the Ethiopian highlands.

Dereje Tesfahun has evaluated how rainfall and other factors affect the flow of the major rivers in Ethiopia. He has used a model to assess how sensitive the flows of the major river basins are affected by the weather and by possible land use changes. His research shows that Ethiopian rivers are sensitive to precipitation with a 10% change in precipitation giving a 20-30% response in annual stream flow.

Diriba Korecha has studied seasonal weather forecast for Ethiopia. He has re-classified the climatic zones in Ethiopia, worked on models to improve seasonal weather forecasting and validated the result of 10 years of seasonal forecasting in Ethiopia. His research shows that seasonal weather forecasting in Ethiopia is difficult.

Adugna Woyessa has studied the prevalence and risks for malaria using prospective community-based surveys in Butajira in the south central Ethiopian Highlands. His study confirms that malaria is present at altitudes as high as 2200 m, and the malaria prevalence increases towards the lowlands. Malaria occurs throughout the year, but mainly after the main rains. One important finding is that he shows that malaria varies much between villages and within households at all altitudes.

Eskindir Loha studies malaria in the holoendemic Arba Minch area. One of his studies shows that models of climate-malaria link vary from place to place, and one model cannot fit all locations. Malaria modelling may need the inclusion of non-climatic causes. In a follow up study he shows that risk of getting malaria varies much both in time and space within villages. He now works on a paper to describe the influence on rainfall, temperature, socioeconomic factors on the incidence on malaria in these lowlands.

Fekadu Massebo is describing the association between resting behaviour, human blood index and entomological inoculation rates of Anopheles arabiensis in south Ethiopia. The studies include analysis on how mosquito density is associated with malaria cases and how it is influenced by temperature and rainfall. He also assesses insecticide resistance pattern, and if simple house screening will reduce risk of malaria infection.

Torleif Markussen Lunde works on the malaria prediction model. He uses information collected from several disciplines of our project. He has developed a validated malaria prediction model. In the coming months, he will produce malaria distribution maps for Ethiopia, and try to estimate how the new IPPC climate scenarios will affect malaria in the coming years.

Ellen Viste has used weather analysis to describe and analyse from where moisture to Ethiopia comes from.  The Indian Ocean, the Congo Basin and the Red Sea are important moisture source regions. The results suggest that most of the air – humid or not – that enters the Ethiopian highlands from the south has travelled through the Indian Ocean, by the African continent, reaching the Ethiopian highlands from the south-west, or through the Turkana channel.

Some conclusions:

The research will reach its research objectives by the end of 2012, and will have produced eight PhDs and over 20 master theses. Based on our experience we conclude the following challenges remain:

Research challenges include:

  • Improve seasonal weather forecasting for Ethiopia
  • Further develop and field-test malaria prediction in close collaboration with national meteorology and health authorities
  • Possibly add new disciplines such as studies on climate – food production and nutrition.

Educational challenges include:

  • Strengthen PhD training in advanced epidemiology and mathematical modelling (both in geophysics and in health research)
  • Strengthening training in medical entomology (masters level)

These are parts we wish to include in plans for a possible extension of our project.

EMAPS 2011 Annual Meeting

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The Ethiopian Malaria Prediction System (EMAPS)  Annual Meeting will be on Monday and Tuesday January 10 and 11 at Ghion Hotel in Addis Ababa.

We plan the meeting as an open scientific meeting, and malaria interested scientists in Ethiopia are invited to take part in the meeting.

We will have one or two lectures at the start of the workshop. Our main emphasis is on forecasting malaria epidemics, and we aim to build our scientific meeting around our modelling efforts.

We shall discuss this in thematic areas such as: mosquito dynamics and behaviour, human host infection (highland, and lowland areas), environmental (hydrology and climate/meteorology), and modelling (captures the whole or part of the information collected so far).

Official statistics underestimate malaria deaths in India

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ResearchBlogging.orgA recent Lancet study (Dhingra, Jha et al. 2010),  show there are 13 times more malaria deaths in India than the World Health Organisation (WHO) estimates. The authors conclude that malaria kills more than 200,000 deaths each year in India. And, the findings suggest that malaria kills not just children, but also adults.

In this study, fieldworkers asked families to describe how their relative died. Two doctors then reviewed each description, and decided if the death cause was malaria. This method is called verbal autopsy.

The WHO disputes these figures, mainly because of the doubt of using verbal autopsies in diagnosing malaria. However, the same organisation (WHO) often recommends such studies to measure mortality rates in communities when vital registration is not available.

This research is important as it raises doubts over the total number of malaria deaths worldwide, including Africa. The findings are consistent with the spatial and temporal epidemiology of malaria in India (Hay, Okiro et al. 2010), and suggest the WHO has underestimated the clinical incidence of malaria in India by a similar order of magnitude.

However, In a recent commentary in Nature, Butler (Butler 2010) discusses that Verbal autopsy is increasingly being questioned by statisticians. On a population level, the aim of verbal autopsy is not to make clinical diagnoses of individual cases, but to estimate the distribution of causes of deaths (cause-specific mortality fractions (CSMFs)). Such a measure is better for setting health-system and research priorities, and to overseeing the effectiveness of disease-control measures.

Dhingra, N., Jha, P., Sharma, V., Cohen, A., Jotkar, R., Rodriguez, P., Bassani, D., Suraweera, W., Laxminarayan, R., & Peto, R. (2010). Adult and child malaria mortality in India: a nationally representative mortality survey The Lancet DOI: 10.1016/S0140-6736(10)60831-8

Butler, D. (2010). Verbal autopsy methods questioned Nature, 467 (7319), 1015-1015 DOI: 10.1038/4671015a

Hay, S., Okiro, E., Gething, P., Patil, A., Tatem, A., Guerra, C., & Snow, R. (2010). Estimating the Global Clinical Burden of Plasmodium falciparum Malaria in 2007 PLoS Medicine, 7 (6) DOI: 10.1371/journal.pmed.1000290

It is difficult to forecast malaria epidemics

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ResearchBlogging.org

Malaria transmission is complex and is associated with climate. However, simple attempts to extrapolate malaria incidence rates from averaged regional meteorological conditions have proven unsuccessful. This study by Loha and Lindtjørn describes P. falciparum malaria incidence models linked with meteorological data in south Ethiopia.

Variability in the models was principally attributed to regional differences, and a single model was not found that fits all locations. Past P. falciparum malaria incidence appeared to be a superior predictor than meteorology. The study concludes that future efforts to model malaria incidence may benefit from inclusion of non-meteorological causes.

This study is agrees with a recent Nature paper by Gething and colleagues. They describe the malaria decline takes place during global warming. The reasons for decline might be non-climatic causes such as better treatment and prevention. The paper by Loha and Lindtjørn shows that factors affecting malaria incidence also varies with a region.

Locally, we are examining possible associations between temperature, rainfall, mosquito development and malaria in both lowlands and highlands in Ethiopia. Through this research, we hope to improve our understanding of the local variations in malaria epidemiology.

Loha, E., & Lindtjørn, B. (2010). Model variations in predicting incidence of Plasmodium falciparum malaria using 1998-2007 morbidity and meteorological data from south Ethiopia Malaria Journal, 9 (1) DOI: 10.1186/1475-2875-9-166

Gething, P., Smith, D., Patil, A., Tatem, A., Snow, R., & Hay, S. (2010). Climate change and the global malaria recession Nature, 465 (7296), 342-345 DOI: 10.1038/nature09098

Global warming and malaria

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ResearchBlogging.orgA recent article by Gething and colleagues in Nature (May 20th, 2010) shows that malaria has declined the past century. The decline has been largest in areas with less malaria transmission.

What is new in this paper is that the malaria decline takes place during global warming. The reasons for decline might be non-climatic factors such as better treatment and prevention. Their research addresses malaria on large scales, and the situation might be different in local areas.

Linking changes in temperatures to variations in malaria epidemiology is justified by known biological effects on life-cycle stages of the Anopheles vector and Plasmodium parasite. For example increasing temperature to 30o C results in shortened sporogonic period of the Plasmodium parasite, and differently for P. falciparum and P. vivax. Higher mean daily temperatures are not favourable for vector survival. Increased temperature speeds up development of the aquatic stages of the vector.

Therefore, some propose developing tools to forecast malaria epidemics. We use different terminology to describe malaria risks, and distinguish between long-term forecasts, early warning and early detection of epidemics.

Long-term epidemic forecasting is based on climate forecasting, and many use information such as the El Niño Southern Oscillation indices as added information to predict epidemic risks months in advance over large geographical areas. Such a forecast allows time for the population to prepare for a possible epidemic in the following malaria season.

Malaria epidemic early warning is based on surveying transmission risks to predict timing of an increase because of abnormal rainfall or temperature. Often, such risks are influenced by population vulnerability such as history of low malaria transmission. Such predictions can give lead times of weeks to months.

The long-term and early warning should however be distinguished from epidemic early detection. This involves noting the beginning of an unusual epidemic, and offers short lead time (days to weeks) for preparation of preventive measures.

We are studying the association between temperature, rainfall, mosquito development and malaria in both lowlands and highlands in Ethiopia. Through this research, we hope to improve our understanding of the local variations in malaria epidemiology. Our aim is to examine if the spatio-temporal distribution of surface temperature and rain can predict malaria epidemics (both long-term forecasting, and malaria epidemic early warning). We base this on an assumption the nature of the link between climate and occurrence of malaria is constant and similar for different settings.

Gething, P., Smith, D., Patil, A., Tatem, A., Snow, R., & Hay, S. (2010). Climate change and the global malaria recession Nature, 465 (7296), 342-345 DOI: 10.1038/nature09098

Malaria mortality declines in Ethiopia

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ResearchBlogging.org BBC World Service citing the Global Fund (Early Evidence of Sustainable Impact on Malaria) reported yesterday that malaria mortality declined by almost 50% in Ethiopia. The Global fund report states a 54% decline in malaria cases and 48% decline in malaria deaths.

Are such figures true? Working on malaria research projects in south Ethiopia I can confirm that fewer malaria patients are admitted to health centres and hospitals. Our preliminary data show that people use bed nets, community health workers diagnose and treat malaria cases, and malaria deaths do not occur as often as previously.

But, we have learned that malaria is a focal disease. In our research on malaria and climate we observe the last years have been dry in large parts of south Ethiopia. After the rains we first see increases in the mosquito densities followed by increases in malaria cases. There are more mosquitoes and cases after the heavy rains in early 2010, compared with 2009. Although we believe that malaria control efforts are effective, we need more time to get a full picture on the links between interventions, malaria sickness and death and naturally occurring variations.

Recent demographic data show decline in under-five mortality rates in Ethiopia from 204 to 123 per 1000 live births between 1990 and 2005. Ethiopia shows good progress was observed in controlling HIV/AIDS and malaria, but not for tuberculosis (Otten M et al, 2009; Accorsi S et al, 2009). Although a downward trend was observed in the maternal mortality ratio, it is too early to reach any firm conclusion about the possibility of achieving MDG5 because of sampling variability (Hogan M et al, 2010).

The good achievements in controlling malaria and increasing immunisation coverage show that scheduled routine interventions is well handled by the current health care system. However, interventions that rely on clinical services near to households with 24h availability, such as skilled care at birth, are weak. With the good achievements on malaria and immunization coverage, Ethiopia now needs to strengthen health institutions such as hospitals and health centres.

Otten, M., Aregawi, M., Were, W., Karema, C., Medin, A., Jima, D., Kebede, W., Gausi, K., Komatsu, R., Korenromp, E., Low-Beer, D., & Grabowsky, M. (2009). Initial evidence of reduction of malaria cases and deaths in Rwanda and Ethiopia due to rapid scale-up of malaria prevention and treatment Malaria Journal, 8 (1) DOI: 10.1186/1475-2875-8-14

Accorsi, S., Bilal, N., Farese, P., & Racalbuto, V. (2010). Countdown to 2015: comparing progress towards the achievement of the health Millennium Development Goals in Ethiopia and other sub-Saharan African countries Transactions of the Royal Society of Tropical Medicine and Hygiene, 104 (5), 336-342 DOI: 10.1016/j.trstmh.2009.12.009

Hogan, M., Foreman, K., Naghavi, M., Ahn, S., Wang, M., Makela, S., Lopez, A., Lozano, R., & Murray, C. (2010). Maternal mortality for 181 countries, 1980–2008: a systematic analysis of progress towards Millennium Development Goal 5 The Lancet DOI: 10.1016/S0140-6736(10)60518-1

The Bergen Summer Research School

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The Bergen Summer Research School aims to produce and disseminate research-based education to address some important global challenges. These challenges include Climate and environmental changes, health challenges and new diseases as well as widespread and severe poverty of certain groups and regions. These issues call for interdisciplinary spaces for debate, and joint learning.

Short description for the 2010 course on Research Methods in Climate Change and Health:

Global climate change may lead to changes in extreme weather events such heatwaves, droughts, extreme rainfall and severe storminess. This may affect human health by bringing about changes in the ecology of infectious diseases. To address the impact of climate change on affect human health a broad research approach including social, demographic, and economic aspects is needed.

The course will explore the links between human health and the earth’s environment, and consider the implications of those links for human health in a changing environment.

The central objective of the course is to help develop and strengthen local and regional scientific knowledge and capacity to deal with the impacts of climate variability and climate change on human health.

For full course description and syllabus: click here (PDF)

The course is by Bjerknes Centre for Climate Research and Centre for International Health at University of Bergen

Course leaders are:

  • Bernt Lindtjørn, Professor, University of Bergen, Centre for International Health
  • Asgeir Sorteberg, Associate Professor, University of Bergen, Bjerknes Centre for Climate Research
  • Ellen Viste, Research Fellow, University of Bergen, Geophysical Institute
  • Thorleif Markussen Lunde, Research Fellow, University of Bergen, Centre for International Health

Doctors and non-physician clinicians (NPC)

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There is a severe shortage of trained health staff in rural Africa. We try to solve this issue by using doctors and non-physician clinicians (NPC). A recent problem we have seen in south Ethiopia is that these two categories of health personnel do not collaborate.

As non-physician clinicians (NPC) take over doing surgical tasks, the doctors withdraw from this important part of the work. General practitioners work on internal medicine and paediatrics, leaving surgery and obstetrics to NPC. In one hospital we have also seen the physician, who has only one year of clinical experience, leave the hospital when the non-physician clinician (NPC) started work.

This is a trend that worries us, and we need to find mechanisms to promote the collaboration between the two professions.

Any suggestions to solve this unhealthy competition?

Drug resistance to artemesinin family of drugs?

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BBC recently reported drug resistance to artesunate drugs (artemesinin family of drugs for malaria treatment) in western Cambodia.

Out of about 90 patients that American scientists studied so far, about a third to half were still positive for malaria parasites after three days, some even after four or five days. This means the drug is not able to kill the parasites quickly enough, and the parasite may develop tolerance or resistance. The reason for resistance is still not known.

If this is a new form of drug resistance that spreads to other countries, its spread would be a global health disaster. Resistance to previous malaria such as chloroquin and fansidar (SF) caused many unnecessary deaths in Africa.

In our study in Chano near Arba Minch, Eskindir Loha is starting a study to monitor possible resistance to Artemether – Lumefantrine  in a few months.

Climate change and health

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Climate change will have more far-reaching effects on health than predicted. The greatest effect will be on the world’spoorest people. This is the main conclusion of a comprehensive report in The Lancet (Lancet 2009; 373: 1693–1733). The indirect effects of climate change on water, food, security,population, migration, and extreme climatic events are likely to have the biggest effect on global health, greater than the increase in vector borne diseases.

Recently, Lafferty (Ecology, 2009, 90: 888–900) wrote that although the globe is warmer than it was a century ago, there is little evidence that climate change has already favoured infectious diseases. Recent models predict range shifts in disease distributions, with some increase of vector borne diseases.

The Lancet report identified some challenges that scientists, doctors, and policy makers need to address:

There is a large information gap, particularly in low and middle-income countries.

The effects of climate change would hit the poor the hardest.

Rich countries should massively reduce their emissions.

There is a  lack of technologies to help people adapt to changes in climate such as measures to boost food production and for storing and treating water

Economic growth is needed in the poor countries to help people to adapt to global warming.