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Golnar A.J.,Texas A&M University | Turell M.J.,U.S. Army | LaBeaud A.D.,Childrens Hospital Oakland Research Institute | Kading R.C.,Centers for Disease Control and Prevention | And 2 more authors.
PLoS Neglected Tropical Diseases | Year: 2014

Rift Valley fever virus (RVFV) is a mosquito-borne virus in the family Bunyaviridiae that has spread throughout continental Africa to Madagascar and the Arabian Peninsula. The establishment of RVFV in North America would have serious consequences for human and animal health in addition to a significant economic impact on the livestock industry. Published and unpublished data on RVFV vector competence, vertebrate host competence, and mosquito feeding patterns from the United States were combined to quantitatively implicate mosquito vectors and vertebrate hosts that may be important to RVFV transmission in the United States. A viremia-vector competence relationship based on published mosquito transmission studies was used to calculate a vertebrate host competence index which was then combined with mosquito blood feeding patterns to approximate the vector and vertebrate amplification fraction, defined as the relative contribution of the mosquito or vertebrate host to pathogen transmission. Results implicate several Aedes spp. mosquitoes and vertebrates in the order Artiodactyla as important hosts for RVFV transmission in the U.S. Moreover, this study identifies critical gaps in knowledge which would be necessary to complete a comprehensive analysis identifying the different contributions of mosquitoes and vertebrates to potential RVFV transmission in the U.S. Future research should focus on (1) the dose-dependent relationship between viremic exposure and the subsequent infectiousness of key mosquito species, (2) evaluation of vertebrate host competence for RVFV among North American mammal species, with particular emphasis on the order Artiodactyla, and (3) identification of areas with a high risk for RVFV introduction so data on local vector and host populations can help generate geographically appropriate amplification fraction estimates. © 2014.

Bublitz D.C.,Genesis Laboratories | Poche R.M.,Genesis Laboratories | Garlapati R.,Genesis Laboratories India Private Ltd
Journal of Arthropod-Borne Diseases | Year: 2016

Visceral leishmaniasis is a deadly parasitic disease that is transmitted via the bite of a female sand fly, Phlebotomus argentipes. The highest burden of this disease is in northern India. In 2005, India embarked on an initiative with Nepal, Bangladesh, and the World Health Organization to eliminate visceral leishmaniasis by 2015. With the goal of 1 case in 10,000 people still unmet, it is prudent to evaluate the tools that have been used thus far to reduce vector numbers and cases of the disease. Herein, we present a review of studies conducted on vector-control strategies in India to combat visceral leishmaniasis including indoor residual spraying, insecticide-treated bed nets, environmental modification, and feed-through insecticides. This review suggests that the quality of indoor residual spraying may enhance control measures while a combination of spraying, nets, and feed-through insecticides would best confront the diverse habitats of P. argentipes.

Wasserberg G.,U.S. Army | Wasserberg G.,University of North Carolina at Greensboro | Poche R.,Genesis Laboratories | Miller D.,Genesis Laboratories | And 3 more authors.
Journal of Vector Ecology | Year: 2011

Our goal was to study the effectiveness of the insecticide imidacloprid as a systemic control agent. First, to evaluate the blood-feeding effect, we fed adult female Phlebotomus papatasi with imidacloprid-treated rabbit blood and monitored blood-feeding success and survival. Second, to evaluate the feed-through effectiveness of this insecticide, we fed laboratory rats and sand rats with insecticide-treated food and evaluated the survival of sand fly larvae feeding on rodents' feces. In the blood-feeding experiment, 89.8% mortality was observed with the higher dose (5 mg/ml) and 81.3% with the lower dose (1 mg/ml). In the larvicide experiments, both sand fly species demonstrated a typical dose-response curve with the strongest lethal effect for the 250 ppm samples. Lutzomyia longipalpis larvae, however, were less sensitive. In all experiments, 1st instar larvae were more sensitive than the older stages. First instar P. papatasi larvae feeding on sand rat feces passed the larvicidal threshold of 90% mortality at doses higher than 50 ppm. In comparison, in older stages 90% mortality was obtained with a dose of only 250 ppm. Overall, results support the feasibility of imidacloprid as a systemic control agent that takes advantage of the tight ecological association between the reservoir host and the sand fly vector. © 2011 The Society for Vector Ecology.

Poche R.M.,Genesis Laboratories | Garlapati R.,Boring Canal Road | Elnaiem D.-E.A.,University of Maryland Eastern Shore | Perry D.,Genesis Laboratories | Poche D.,Genesis Laboratories
Journal of Vector Ecology | Year: 2012

Visceral leishmaniasis (VL), known as Kala-azar in India, is a parasite transmitted by the bite of the sand fly vector Phlebotomus argentipes. Published information on the species indicates it is a poor flyer, mainly hopping and gliding. This study describes the vector as more arboreal than previously documented. Data collected indicate the ability of P. argentipes and Sergentomyia spp to attain vertical heights in Palmyra palm trees Borassus flabellifer up to 18.4 m above ground level. To determine if sand flies were either climbing the tree trunk to rest in the canopy or flying, sticky traps were set around the tree trunk and checked for captures overnight. CDC traps set in the palm tree canopy resulted in the capture of 5,067 sand flies, 3,990 of which were P. argentipes. Traps were set during daylight hours to determine if sand flies remained and rested in the canopy. A total of 128 sand flies were trapped over 29 trap days in the palm trees. With the CDC traps, 130 P. argentipes and no Sergentomyia spp were captured. The converse was true for the sticky traps set around tree trunks 3 m below the CDC traps. Of the 105 sand flies collected, only one was P. argentipes and 104 were Sergentomyia spp. As reported elsewhere, this indicates Sergentomyia spp tend to climb and hop, wheareas P. argentipes are capable of longer and more sustained flight. Data presented herein suggest that P. argentipes is more exophylic and exophagic than previously reported. These findings have implications for sand fly control. © 2012 The Society for Vector Ecology.

Lozano-Fuentes S.,Genesis Laboratories | Kading R.C.,Genesis Laboratories | Kading R.C.,Colorado State University | Hartman D.A.,Genesis Laboratories | And 4 more authors.
Malaria Journal | Year: 2016

Background: Although vector control strategies, such as insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS) have been effective in Kenya the transmission of malaria continues to afflict western Kenya. This residual transmission is driven in part by Anopheles arabiensis, known for its opportunistic blood feeding behaviour and propensity to feed outdoors. The objective of this research was to evaluate the efficacy of the drug eprinomectin at reducing malaria vector density when applied to cattle (Bos indicus), the primary source of blood for An. arabiensis, under field conditions. Methods: A pilot study was carried out in the Samia District of western Kenya from September to October of 2014. Treatment and control areas were randomly designated and comprised of 50 homes per study area. Before cattle treatments, baseline mosquito counts were performed after pyrethrum spray. Cows in the treatment area were administered topical applications of eprinomectin at 0.5 mg/kg once a week for two consecutive weeks. Mosquito collections were performed once each week for two weeks following the eprinomectin treatments. Mosquitoes were first identified morphologically and with molecular confirmation, then screened for sporozoite presence and host blood using PCR-based methods. Results: The indoor resting density of An. arabiensis was significantly reduced by 38 % in the treatment area compared to the control area at one-week post-treatment (Control mean females per hut = 1.33 95 % CI [1.08, 1.64]; Treatment = 0.79 [0.56, 1.07]). An increase in the indoor resting density of Anopheles gambiae s.s. and Anopheles funestus s.s. was observed in the treatment area in the absence of An. arabiensis. At two weeks post-treatment, the total number of mosquitoes for any species per hut was not significantly different between the treatment and control areas. No change was observed in An. arabiensis host preference as a result of treatment. Conclusions: Systemic drugs may be an important tool by which to supplement existing vector control interventions by significantly impacting outdoor malaria transmission driven by An. arabiensis through the treatment of cattle. © 2016 The Author(s).

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