avian malaria

Research Project | 2016

Avian Malaria

Plasmodium parasites like those that cause malaria in humans also infect birds.  Parasites are known to play an important role in host population dynamics and evolution, and mosquitoes infected with protozoan parasites exhibit modified behavior that increases their vectorial capacity. It has been documented that malaria-infected mosquitoes bite more frequently. With increasing loss of biodiversity, infectious diseases appear to be emerging and reemerging at a faster rate. Research on the links between these two conditions can have an important impact on our view of biodiversity and the services provided by natural ecosystems and how we manage them.

Given the relevance of mosquitoes as vectors of malaria, one would expect that all of these aspects would have been investigated in greater detail. In general, the spatial dynamics of the various mosquito species are poorly understood and there has been relatively little spatially-explicit research on them.

Our work focuses on sampling Culicine mosquitoes in malaria-endemic areas of Cameroon with three main objectives

1) Gauge the effects of deforestation on the diversity and host-specificity of avian malaria parasites in Cameroon.

2) Measure the effects of deforestation on mosquito communities.

3) Identify habitat effects on vectors that transmit generalist and specialist malaria parasites.

Our results may prove critical for understanding the seasonal disease outbreaks that occur in some habitats as well as help develop interdisciplinary tools and methods to forecast and mitigate risks to biodiversity and health.

 

Avian Malaria, Mosquitoes, and Birds in Cameroon

Pathogens have a high relevance for conservation, particularly in localities in which human influences are high. With increasing loss of biodiversity, infectious diseases appear to be emerging and reemerging at a faster rate. Research on the links between these two conditions can have an important impact on our view of biodiversity and the services provided by natural ecosystems and how we manage them.

Avian malaria has long been of interest as a model for the study of various aspects of human malaria. Its almost worldwide distribution and ease of maintenance through blood passage has enabled the elucidation of many aspects of the schizogonic stages of its life cycles in birds (the vertebrate host). The malaria parasite depends upon mosquitoes to transmit it from host to host (Fig. 1). Within the host, the parasite develops into two forms. One form reproduces asexually (schizogonic stage) within red blood cells which then burst and release offspring to infect more red blood cells. These rounds of reproduction provoke malaria’s characteristic fevers. The other form of the parasite reproduces sexually (sporogonic stage), does not cause symptoms, and is transmitted to mosquitoes. Much less attention has been paid to studying the sporogonic cycles in mosquitoes. Given the relevance of mosquitoes as vectors of malaria, one would expect that all of these aspects would have been investigated in greater detail. In general, the spatial dynamics of the various mosquito species are poorly understood and there has been relatively little spatially-explicit research on them.

Our work focuses on sampling Culicine mosquitoes in malaria-endemic areas of Cameroon and using multiplex Polymerase Chain Reaction (PCR) techniques to provide information about the status of malarial infection and genetics of the host, vector, and parasite. Culicine mosquitoes are the primary vectors of malaria in tropical Africa and their abundance and attributes, such as feeding habits and host preference, vary greatly from one species to another. Their feeding habits constitute a significant aspect of their vectorial capacity.

Our results may prove critical for understanding the seasonal disease outbreaks that occur in some habitats as well as help develop interdisciplinary tools and methods to forecast and mitigate risks to biodiversity and health.

avian-malaria

Fig. 1. Malaria parasites belong to the Plasmodiumgenus and infect many types of mammals and birds. Only certain species of mosquitoes carry the parasites. Infected birds are fed on by local mosquitoes that can pass the parasite through future bites.

Related Publications

Coevolutionary patterns and diversification of avian malaria parasites in African Sunbirds (Family Nectariniidae)

Lauron, E. J.; Loiseau, C.; Bowie, R. C.; Spicer, G. S.; Smith, T. B.; Melo, M.; Sehgal, R. N.

Published Work | 2014 | Parasitology 142(5), 635-647

Novel statistical methods for integrating genetic and stable isotope data to infer individual-level migratory connectivity

Rundel, C. W.; Wunder, M. B.; Alvarado, A. H.; Ruegg, K. C.; Harrigan, R.; Schuh, A.; Kelly, J. F.; Siegal, R. B.; DeSante, D. F.; Smith, T. B.; Novembre, J.

Published Work | 2013 | Molecular Ecology 22(16), 4163–4176

Feeding habits of culicine mosquitos in the Cameroon lowland forests based on stable isotopes and blood meal analyses

Njabo, K. Y.; Smith, T. B.; Yohannes, E.

Published Work | 2013 | Journal of Parasitology and Vector Biology 5, 6–12

The ecology of emerging infectious diseases in migratory birds: an assessment of the role of climate change and priorities for future research

Fuller, T.; Bensch, S.; Muller, I.; Novembre, J.; Perez-Tris, J.; Ricklefs, R. E.; Smith, T. B.; Waldenstrom, J.

Published Work | 2012 | EcoHealth 9, 80–88

Host and habitat specialization of avian malaria in Africa

Loiseau, C.; Harrigan, R. J.; Robert, A.; Bowie, R. C.; Thomassen, H. A.; Smith, T. B.

Published Work | 2011 | Molecular Ecology 21(2), 431–441

Nonspecific patterns of vector, host and avian malaria parasite associations in a Central African rainforest

Njabo, K. Y.; Cornel, A. J.; Bonneaud, C.; Toffelmier, E.; Sehgal, R. N.; Valkiunas, G.; Russell, A. F.; Smith, T. B.

Published Work | 2010 | Molecular Ecology 20(5), 1049–1061

Spatially explicit predictions of blood parasites in a widely distributed African rainforest bird

Sehgal, R. N.; Buermann, W.; Harrigan, R. J.; Bonneaud, C.; Loiseau, C.; Chasar, A.; Sepil, I.; Valkiunas, G.; Iezhova, T.; Saatchi, S.; Smith, T. B.

Published Work | 2010 | Procedings of the Royal Society B 278, 1025–1033

Spatial variation of haemosporidian parasite infection in African rainforest bird species

Loiseau, C.; Iezhova, T. A.; Balkiunas, G.; Chasar, A.; Hutchinson, A.; Buermann, W.; Smith, T. B.; Sehgal, R. N.

Published Work | 2010 | Journal of Parasitology 96, 21–29

Coquillettidia (Culicidae, Diptera) mosquitoes as new natural vectors of avian malaria in Africa

Njabo, K. Y.; Cornel, A. J.; Sehgal, R. N.; Loiseau, C.; Buermann, W.; Harrigan, R. J.; Pollinger, J.; Valkiūnas, G.; Smith, T. B.

Published Work | 2009 | Malaria Journal 8

The prevalence of avian Plasmodium is higher in undisturbed tropical forests of Cameroon

Bonneaud, C.; Sepil, I.; Milá, B.; Buermann, W.; Pollinger, J.; Sehgal, R. N.; Valkiūnas, G.; Iezhova, T. A.; Saatchi, S.; Smith, T. B.

Published Work | 2009 | Journal of Tropical Ecology 25, 439–447

New malaria parasites of the subgenus Novyella in African rainforest birds, with remarks on their high prevalence, classification and diagnostics

Valkiūnas, G.; Iezhova, T. A.; Loiseau, C.; Chasar, A.; Smith, T. B.; Sehgal, R. N.

Published Work | 2008 | Parasitology Research 104, 1061–1077

Further observations on the blood parasites of birds in Uganda

Valkiunas, G.; Sehgal, R. N.; Iezhova, T. A.; Smith, T. B.

Published Work | 2005 | Journal of Wildlife Diseases 41(3), 580–587

Blood parasites of some West African rainforest birds

Sehgal, R. N.; Jones, H. I.; Smith, T. B.

Published Work | 2005 | Journal of Veterinary Medical Science 67(3), 295–301

A comparative analysis of PCR-based detection methods for avian malaria

Richard, F. A.; Sehgal, R. N.; Jones, H. I.; Smith, T. B.

Published Work | 2002 | Journal of Parasitology 88(4), 819–822