In nature, vertebrate hosts of arboviruses are often infected with other parasitic organisms. Laboratory studies have established that vertebrates concurrently infected with microfilariae and arboviruses can enhance mosquito transmission of arboviruses. When ingested, microfilariae penetrate the mosquito midgut and allow immediate dissemination of virus into the mosquito body cavity. This greatly increases and accelerates viral infectivity of mosquitoes. This is termed mf enhancement of arboviral transmission and it can have 2 important epidemiological consequences. First, mosquito species that are normally refractory to viral infection because of midgut barriers to viral infectivity may now develop infections. Thus, otherwise incompetent vector species can be transformed into competent vector species, increasing the number of vector species involved in a virus transmission cycle. Second, microfilarial enhancement can accelerate viral development within the mosquito, significantly shortening the time required for infected mosquitoes to become infectious mosquitoes (=extrinsic incubation period EIP]). Since EIP affects transmission in an exponential fashion, small reductions in EIP can lead to large increases in vectorial capacity, even with natural vector systems. Hypothesis: the phenomenon of microfilarial enhancement may affect the transmission of dengue virus in certain areas of the world where the distribution of dengue and human filariasis overlap. The objective of this proposal is to understand the magnitude to which human filariasis can affect patterns of dengue transmission under varying conditions. The experimental approach is to utilize an existing computer simulation model for dengue transmission (DENSiM) to predict how different types and prevalence's of human filariasis can alter transmission dynamics of dengue virus by Aedes spp. mosquitoes. Important parameters for transmission (e.g., EIP) will be determined experimentally with the use of paired mosquito feedings. Viral development and transmission will be compared between dually exposed (i.e., virus plus mf) versus singly exposed (i.e., virus only) mosquitoes, examining different serotypes of dengue viruses and different species of filarial parasites. Using a combination of laboratory-derived data and computer simulation, it is anticipated that fundamental principles can be established that will be generally applicable to any arboviral transmission cycle where arboviral and micro filarial infections occurs together.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI049477-01
Application #
6323678
Study Section
Special Emphasis Panel (ZRG1-TMP (01))
Program Officer
Aultman, Kathryn S
Project Start
2001-04-01
Project End
2003-03-31
Budget Start
2001-04-01
Budget End
2002-03-31
Support Year
1
Fiscal Year
2001
Total Cost
$172,082
Indirect Cost
Name
University of North Dakota
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
102280781
City
Grand Forks
State
ND
Country
United States
Zip Code
58202
Vaughan, Jefferson A; Mehus, Joseph O; Brewer, Christina M et al. (2012) Theoretical potential of passerine filariasis to enhance the enzootic transmission of West Nile virus. J Med Entomol 49:1430-41
Vaughan, Jefferson A; Focks, Dana A; Turell, Michael J (2009) Simulation models examining the effect of Brugian filariasis on dengue epidemics. Am J Trop Med Hyg 80:44-50
Bell, Jeffrey A; Brewer, Christina M; Mickelson, Nathan J et al. (2006) West Nile virus epizootiology, central Red River Valley, North Dakota and Minnesota, 2002-2005. Emerg Infect Dis 12:1245-7
Bell, Jeffrey A; Mickelson, Nathan J; Vaughan, Jefferson A (2005) West Nile virus in host-seeking mosquitoes within a residential neighborhood in Grand Forks, North Dakota. Vector Borne Zoonotic Dis 5:373-82
Vaughan, Jefferson A; Sonenshine, Daniel E; Azad, Abdu F (2002) Kinetics of ingested host immunoglobulin G in hemolymph and whole body homogenates during nymphal development of Dermacentor variabilis and Ixodes scapularis ticks (Acari: Ixodidae). Exp Appl Acarol 27:329-40