ENTOMOLOGY & VECTOR BORNE DISEASE
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Recent Studies

(2005-2007) Integrated Control Methods for Sand Fly Vectors. Collaborating with WRAIR. This is a 3 year, multilab study coordinated by WRAIR. It involves CRADAs with two bed net manufactures. The study involves 1 year of vector surveillance to establish the baseline density of sand fly populations (already complete) followed by 2 years of control method testing. Control methods to be evaluated include: various insecticide treated bed nets (ITNs), insecticide treated tents, residual insecticide treatment if larval habitat, barrier insecticide spraying.

Objectives: To test and improve control methods for sand flies with the aim of developing an integrated sand fly control system.

(2006) Malaria Dipstick Assay Validation. Collaborating with WRAIR, we are validating a reformulation of the malaria (P. falciparum and P. vivax 247) dipstick under development. 

(2006) Validation of a rapid detection tool for Leishmania surveillance in vector populations. In collaboration with Dr. Chan at WRAIR, we are conducting field testing of a rapid diagnostic assay for leishmaniasis.

Background/Summary: This project is part of an SBIR (OSD04-H08) for the “Development of a field-usable diagnostic device for the detection of Leishmania parasite in sand flies” (awarded in January 2005). The second phase of this 2 year study will involve a field test of prototype assays using real-time PCR as a standard reference. The DoD overseas sites that will be participating are Egypt (NAMRU-3), Indonesia (NAMRU-2), Peru (NMRCD), Kenya (USAMRU-K) and Iraq. Prototype assays will be tested in Kenya with sand flies collected in Baringo.

Objectives: The objective of this project is to develop a Leishmania detection assay which is field portable, user-friendly, rapid (<30 min) and stable at ambient temperatures. In 2004, the Walter Reed Army Institute of Research Entomology Department and VecTOR Test Systems Inc, California, began developing field-usable wicking assays to detect the parasites in sand flies.

(2006-2007) RT-PCR and “dipstick” pathogen detection assays (collaboration with WRAIR and USAMRIID).Our role in this study is to provide logistical and site support to a 3 person team from USAMRIID which will conduct 4, 2 week visits to Kenya to test the assays they have developed. 

Objectives: To develop, evaluate, and compare the specificity and sensitivity of real-time PCR and conventional PCR, for the detection of viral and parasitic pathogens (CCHF, RVFV, SFFV, WNV, Karshi virus, JEV, TBEV, malaria, scrub typhus, and Leishmania) isolated from arthropod vectors in the field. Field evaluations designed to compare the ease of use, the specificity, and the reliability of real-time PCR and conventional PCR for better integration into field medical units.

(2006-2007) Arbovirus surveillance

Objectives: 
To update the regional arbovirus threat assessment.
To estimate the diversity and prevalence of key viruses in arthropods during an inter-epidemic period;
Determine the vector species that contribute to the maintenance and/or amplification of these arboviruses.

(2002-2005) Characterization of malaria transmission in Western Kenya. Started as a multi-year project in mid-2002 in support of a new vaccine study site when the malaria vaccine program moved to a new study site in the vicinity of Kombewa to establish the relative importance of An. gambiae and An. funestus, determine biting pressure and malaria infectivity of the vector, and study the dry season ecology of An. gambiae. This project is on-going.

(2002) Validation of the VecTest malaria panel dipstick assay. In collaboration with Jeff Ryan and WRAIR. Three separate studies using 5,000 mosquitoes each, each mosquito was assayed using the VecTest strips, and a comparative sporozoite ELISA was performed on each, which demonstrated positive efficacy leading to manufacture and dissemination of the Malaria VecTest. (Published data – see below).

(2002) Anopheles gambiae immune gene variant project. In collaboration with Dr. Shirley Luckhart, USAMRU-K managed the field portion of this study, involving two Anopheles collection trips each to Western Kenya and the Kenya coast. (Published data – see below).

(2002) Rift Valley Fever outbreak investigation. In conjunction with the CDC, USAMRU-K, Entomology collected approximately 80,000 mosquitoes in areas of recent RVF activity in an attempt to verify vector transmission. Mosquitoes transported to Dr. Peter Jupp in South Africa.

(2002-2003) Spotted fever rickettsiosis in Kenya. Prompted by deficiencies in the understanding of the epidemiology of African Tick Bite Fever (ATBF) throughout most of sub-Saharan Africa and a recent ATBF case report, we adopted an integrated approach employing entomological investigations, remote sensing, and GIS to examine the risk of ATBF in the Maasai Mara Region of Kenya. We have determined the presence of the spotted fever group rickettsiae (SFG) in Maasai Mara mainly in Amblyomma variegatum ticks.

(2005) Alphavirus Surveillance. In collaboration with CDC, GEIS, and several Kenyan organizations, we are part of a group established as a follow-up to the hemorrhagic investigations conducted in Lamu and Mombassa, Kenya. The group maintains a response capability in preparation for future outbreaks in east Africa.

(2005) Rift Valley Fever Virus (RVFV) Group. In collaboration with CDC, and several Kenyan organizations, we conduct the entomological support for this effort to survey for RVFV in Kenya.