icipe Governing Council Student Awards 2015

First Prize: Xavier Cheseto

icipe supervisors: Prof. Baldwyn Torto  and Dr David Tchouassi

Cheseto X., Kuate S.P., Tchouassi D.P., Ndung’u M., Teal P.E.A. and Torto B. (2015) Potential of the desert locust Schistocerca gregaria (Orthoptera: Acrididae) as an unconventional source of dietary and therapeutic sterols. PLOS ONE 10, e0127171. doi:10.1371/journal.pone.0127171

Contribution to science:  This paper published in PLOS ONE (impact factor 3.234) provides insights into the increasing recognition of insects not only as an environmentally- friendly source of food to feed the ever growing world population but also as potential sources of new products and therapeutic agents. Although notorious for its crop destructive role, the authors findings showed that the desert locust ingests phytosterols through a vegetative diet and, amplify and metabolize them into novel derivatives known to have potential human health benefits. The major sterols and phytosterols detected in the desert locust included: β-Sitosterol, Campesterol, Stigmasterol, 7-dehydrocholesterol, desmosterol, lanosterol and fucosterol.   These compounds have been reported to be important towards; prostrate health, cardiovascular diseases, cholesterol homeostasis, anticancer, weight loss, rheumatoid arthritis, immune boosting and anti-inflammatory. These, combined with its rich nutritional composition in terms of proteins, fatty acids and minerals, truly qualify the desert locust as a nutritious food source for both humans and animals. The findings impact on entomophagy by providing an additional nutritive value of the desert locust which has been reputed for its alarming threat to food security, for instance, through major outbreaks in the Sahel region of Africa, known to destroy crops over large expanse of land. The landmark publication led to widespread media coverage both locally and internationally.  The finding creates an emerging dimension into desert locust focusing on exploiting its potential as a component of food and nutritional security in Africa.  The desert locust is known to contain high protein, fiber, minerals and fatty acid and comparable to conventional meat like beef. This study reports it to contain phytosterols, which is good for the heart, an example is β-Sitosterol. This compound is available commercially as a supplement but is very expensive (Amazon: 90 capsules costing USD 100).  The same compound and other phytosterols can be acquired through consumption of the desert locust. Further benefit and potential for commercialization as food abound through development of mass rearing and harvesting techniques, processing and packaging, food safety and policy issues and socioeconomic assessment as well as cost-effective isolation of useful products.

Second Prize: Edith Chepkorir

icipe supervisor: Dr. Rosemary Sang

Chepkorir E., Lutomiah J., Mutisya J., Mulwa F., Limbaso K., Orindi B., Ng’ang’a Z. and Sang R. (2014): Vector competence of Aedes aegypti populations from Kilifi and Nairobi for dengue 2 virus and the influence of temperature. Parasites & Vectors 2014 7:435. doi:10.1186/1756-3305-7-435

Contribution to science:  Published in Parasites & Vectors (impact factor 3.430) this manuscript presents insights on the first initial effort to understand the role of Ae. aegypti in driving dengue transmission in Kenya, and to assess the risk of further spread of the disease by analyzing the vector competence of Ae. aegypti populations from parts of Kenya and the influence of environmental factors like temperatures that prevail in outbreak hotspots and other areas of potential risk. In the backdrop of dengue re-emergence in Kenya and the region, there is need to continuously update our knowledge base for a better mechanistic understanding of the environmental determinants of vector pathogen interactions.  Currently, dengue fever is one of the important public health concerns in Kenya with outbreaks occurring in Coastal and Northern parts of Kenya causing considerable morbidity and economic losses due to lost man hours. Dengue has no effective treatment and disease prevention and control relies mainly on vector control. It is important to determine vector competence of Kenyan Ae. aegyptipopulations to establish the level of risk of dengue virus transmission in the region and country.  In this paper, vector competence of two Ae. aegypti populations from Nairobi and Kilifi were compared for dengue 2 virus. The paper reports that both mosquito populations are susceptible to dengue-2 virus, but only Kilifi population supporting disseminated infection and transmission. The findings also suggest an inefficient transmission ability of dengue-2 virus by the NairobiAe. aegypti population hence explaining why there has been no evidence of active dengue transmission in Nairobi despite reported cases of dengue in health facilities usually from individuals who have travelled from Mombasa (coast) and/or Mandera (North-eastern Kenya) where outbreaks have been reported.  The paper also reports on how environmental temperature has a significant effect on the vector competence as demonstrated by significantly higher infection rates of dengue-2 virus at high temperatures for Ae. aegypti mosquitoes from both Nairobi and Kilifi. The findings highlight that the variation in vector competence among the populations of Ae. aegypti examined may help explain the distribution and spread of dengue fever. As the impact of climate change leads to increasing temperatures, spread of the virus through local vectors into susceptible host populations becomes likely. 

Third Prize: Purity N. Kipanga

icipe supervisors: Dr. Jandouwe Villinger and Dr. Daniel Masiga 

Kipanga P.N, Omondi D., Mireji P.O, Sawa P., Masiga D.K. and Villinger J. (2014): High-resolution melting analysis reveals low Plasmodium parasitaemia infections among microscopically negative febrile patients in western Kenya. Malaria Journal 2014 13:429. doi:10.1186/1475-2875-13-429

Contribution to science: The authors developed an innovative malaria diagnostic platform, nested PCR with high resolution melting analysis (nPCR-HRM) that was published in Malaria Journal (impact factor 3.109). This novel approach combines the high sensitivity potential of nested Polymerase chain reaction (nPCR) with the species differentiating capabilities of direct PCR-HRM (dPCR-HRM). The authors not only were able to detect and differentiate lowPlasmodium parasitemia undetected by microscopy and rapid diagnostic test kits (RDTs) and hence pave way for improved differential diagnosis of diseases, but also were the first to successfully quantify anti-malarial drug prescription patterns among microscopically negative febrile patients. The nPCR-HRM platform was capable of detecting low parasitemia as low as 236 parasites/mL of blood, greatly improving detection resolution compared to dPCR-HRM (1,490 parasites/mL) and nPCR (4,700 parasites/mL).  Additionally, only the coupled nPCR-HRM system was able to detect dual and triple infections of Plasmodium falciparum, P. malariae and P. ovale with precision. Among study samples from rural clinics of Rusinga and Mfangano Islands, nPCR-HRM enabled quantification of misadministration of anti-malarial drugs on patients without detectable Plasmodium parasites. Approximately one third of patients had low parasitaemia Plasmodium infections, and 81.5% of febrile illness patients without detectable parasitaemia were treated with antimalarial drugs.  This novel and robust molecular platform not only has profound connotations to the general scientific community in terms of new knowledge and multiple applications, it also has positively contributed to the malaria-control research fraternity. In particular, this diagnostic tool can be used in monitoring lowPlasmodium parasitemia among populations for treatment to reduce transmissions in malaria endemic regions and for regional elimination efforts. Low Plasmodium parasitemia contributes to human infectious reservoir and if undetected, can water down the advances already made to eliminate malaria transmissions and new infections.  The tool can also be used to complement microscopy and RDTs to monitor specific Plasmodium infection rates in humans as well as mosquito vectors.