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Partnerships for enhanced engagement in research (PEER)
Cycle 4 (2015 Deadline)

Using geospatial tools to investigate how deforestation affects the transmission of malaria in birds

PI: Anong Damian Nota (, University of Buea
U.S. Partner: Thomas Smith, University of California, Los Angeles
Project Dates: November 2015 - October 2018

Project Overview

4-360 Nota_bird
Photo courtesy of Dr. Nota

This project addresses an unsolved problem in the field of emerging diseases: What are the proximal effects of large-scale deforestation on the transmission of vector-borne infectious diseases? The principal investigator and his team will approach this problem by studying malaria in natural populations of rainforest birds threatened by rapid environmental degradation in Cameroon. It is well established that deforestation poses a major threat to biodiversity in tropical regions; however, its effects on the spread of pathogens are largely uncharacterized. The team has previously identified malaria parasites, both generalists and specialists, in African rainforest birds, and they have found that it is the generalists that have the potential to jump to naïve hosts and develop as emerging diseases. They have also identified mosquito vectors of avian malaria and demonstrated that patterns of malaria diversity are significantly affected by habitat. With their knowledge of sectors presently zoned for logging, they thus have in place an unprecedented model system for investigating the effects of environmental change on disease transmission. They will test the hypotheses that (1) deforestation promotes an increase in ther prevalence of generalist parasites and (2) vector species distributions change with deforestation, and account for differences in prevalence of generalist vs. specialist parasites. The ultimate goal of this research is to discern the interplay among hosts, habitat, and vector ecology on the potential spread of novel pathogen strains. Another important objective is to determine how human-altered environments affect the feeding patterns of insect vectors and what environmental factors are important in determining likelihood of transmission. By applying the same type of relations before and after logging, they researchers should be able to predict where the vectors are likely to occur, where disease is likely to occur, and the patterns may change.

This work will capitalize on the U.S. Government-supported partner’s expertise in molecular biology, parasitology, entomology, and fieldwork and leverages the archive of blood samples that the he and his collaborators have accrued over nearly 30 years from African rainforest birds. 

Summary of Recent Activities

The second year of this project continued to address the laid down objectives. Fieldwork continued with the revisiting of sites that had been slated for logging and the development of palm oil plantations. The same schedule of quarterly visits were carried out to monitor bird and mosquito populations, while collecting avian blood samples and vectors in same sites that they visited in the first year. Each sampling session lasted for 3 weeks.

Sithe Global-Sustainable Oils Cameroon (SG-SOC) carried out selective Logging in two of the sites where they had established transects and this greatly opened up the forest in these areas. They visited these same sites last year per their deforestation plans. Two other sites remained intact as SG-SOC had modified the logging plans, but this sampling will still be important in assessing before-after control-impact pairs (BACIP) on the status and diversity of the parasites in birds and mosquitoes over time.

Correlation of parasite prevalence, temperature and humidity was studied by continuous monitoring of deforestation on microclimatic conditions using our HOBO U23.002 data loggers. This monitoring was done hourly at our sampling sites during each sampling season. As in the previous year, each of these data loggers were checked every 3 months. 

The team has been carrying out sampling after every 3 months between October 2016 and July 2017. Each of their field sampling effort (for birds and mosquitoes) lasted for 3 weeks per field trip. They have been collecting blood samples from all captured bird species, using our standard mist netting procedures as has been described in previous reports. The most common species captured in their nets have been: Cyanomitra olivacea, Andropadus latirostris, Phyllastrephus icterinus, Bleda notatus, Alcedo leucogaster, Eurillas virens, Neocosssphus poensis, Hylia prasina, Stiphrornis erythrothorax, and Alethe castanea. Occasionally some interesting none passerine birds such as Accipiter tachiro fell in their mist nets. As of date, over 1649 birds of different species have been captured and banded with numbered metal bands, measured for morphometrics (i.e. weight, tarsus and wing length, bill depth) and released.

The collection of mosquitoes continued as in the previous year concurrently with the sampling of the vertebrate hosts, that is, every 3 months between October 2016 and July 2017. The PI's US collaborators from the University of California Davis, Dr Anton Cornel, and Dr Ravinder Sehgal from San Francisco State University travelled to Cameroon for the second year and worked with the students in the PI’s lab at the University of Buea. Dr Sehgal assisted in the field as well as screening of avian samples in the lab while Dr Cornel continued with training of the students on morphological identification of preserved unidentified mosquitoes and in the dissection of male mosquito genitalia. This is an important requirement in species identification, especially species of the complicated Culex complex. So far, over 6,744 mosquitoes belonging to 47species and 10 genera have been identified. 6 potential new species of the genus Eretmopodites have been described based on the genitalia observed.

All data collected so far in the project have been keyed into Microsoft Excel Pending analysis. Students have received training over the one and a half years on the use of the statistical package R as well as participated in the University of California organized Bioinformatics Workshops. Three computers have been purchased and equipped with software (R, Maxent and QGIS) for students from all the three institutions (universities of Buea, Dschang and HIES) to be able to develop skills for data analysis. They have started cleaning sequences obtained in preparation for bioinformatics analysis.

The Tropical Biodiversity and Conservation Program, an NSF PIRE-sponsored program jointly coordinated by Drexel University, the University of California Los Angeles (UCLA), and the Central Africa Biodiversity Alliance (CAB Alliance) organized an intensive 3 week field course in Cameroon. This course, geared towards university students, had a strong focus on hands-on experiential learning and training in biodiversity research.

Co-PI Kevin Njabo was elected to the position of Global Vice President of the Society for Conservation Biology (SCB). He attended the Board of Governors Meeting in Cartegena Colombia from July 28-30, 2017. All the PI's students are now members of the SCB, through the Cameroon chapter

Two of the students will travel to the US for more training on mosquito systematics, PCR extraction and sequencing at the lab of the US collaborator, Dr Anton Cornel. They also expect the students to visit the lab of
their US supported partner Dr Thomas B Smith and work with co-PI Dr Kevin Njabo as they prepare manuscripts for publication based on data already collected.

Dr. Nota expects field work to continue as they move into the third year to collect more blood samples from birds and to collect more mosquitoes from the established transects. The shift in collection of samples will move todeforested areas already being converted to palm plantations following the plans of SC-SOC.

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