Schistosoma mansoni is one of the world's most common infectious organisms. It continues to afflict poor people, especially children, in much of the developing world and most prominently in tropical Africa. We propose a series of studies to investigate the potential impact of several relevant selective factors on the biology of this parasite, both in its molluscan and human hosts. The proposed studies will be done in collaboration with Dr. Gerald M. Mkoji of the Kenya Medical Research Institute (KEMRI) and will take place in Kisumu, Kenya, near Lake Victoria. Our efforts will interface with those of an ongoing KEMRI project undertaken in collaboration with the Center for Disease Control and Prevention (CDCP), headed by Dr. Diana Karanja of the Kisumu KEMRI office and Dr. Evan Secor of the CDCP. The KEMRI-CDCP study has enrolled -300 human subjects in a long-term study exploring the immunobiology of S. mansoni, including its interactions with HIV-I. Largely from the same pool of human subjects we will obtain miracidia from fecal samples and develop methods for assessing the genetic diversity among miracidia as a means to make inferences about the adult worm populations harbored by humans. We also will adapt new assays to detect praziquantel (PZQ) susceptibility of both miracidia and cercariae. With these tools, we will determine if and how concurrent HIV infection or PZQ exposure, including repeated exposure, alter the genetic composition of S. mansoni, or favor the emergence of PZQ resistance. We will also look for signs of genetic introgression of a sympatric and closely related parasite, Schistosoma rodhaini, that we know hybridizes with S. mansoni in the Lake Victoria area. We will examine naturally infected snails to learn if they emit cercariae at unusual times of the day as a practical indicator of hybridization, and determine if multiple parasite genotypes are present within individual snails. Cercariae from these snails will also be tested for their responsiveness to PZQ. Finally we will undertake experimental snail infections to better understand how schistosome infections are acquired by snails in Kisumu, and to learn if S. mansoni and S. rodhaini either compete or cooperate to achieve infections in the snail host. Our studies will develop new epidemiological tools, create unique synergies with the KEMRI-CDCP project and will enable us to better understand how S. mansoni will respond to the vast environmental changes underway in Africa today.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI044913-10
Application #
7393821
Study Section
Special Emphasis Panel (ZRG1-TMP (99))
Program Officer
Costero, Adriana
Project Start
1999-04-01
Project End
2010-04-30
Budget Start
2008-05-01
Budget End
2010-04-30
Support Year
10
Fiscal Year
2008
Total Cost
$263,935
Indirect Cost
Name
University of New Mexico
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
868853094
City
Albuquerque
State
NM
Country
United States
Zip Code
87131
Brant, Sara V; Loker, Eric S; Casalins, Laura et al. (2017) Phylogenetic Placement of a Schistosome from an Unusual Marine Snail Host, the False Limpet (Siphonaria lessoni) and Gulls (Larus dominicanus) from Argentina with a Brief Review of Marine Schistosomes from Snails. J Parasitol 103:75-82
Brant, S V; Pomajbikova, K; Modry, D et al. (2013) Molecular phylogenetics of the elephant schistosome Bivitellobilharzia loxodontae (Trematoda: Schistosomatidae) from the Central African Republic. J Helminthol 87:102-7
Steinauer, Michelle L; Christie, Mark R; Blouin, Michael S et al. (2013) Non-invasive sampling of schistosomes from humans requires correcting for family structure. PLoS Negl Trop Dis 7:e2456
Hanelt, Ben; Bolek, Matthew G; Schmidt-Rhaesa, Andreas (2012) Going solo: discovery of the first parthenogenetic gordiid (Nematomorpha: Gordiida). PLoS One 7:e34472
Steinauer, Michelle L; Blouin, Michael S; Criscione, Charles D (2010) Applying evolutionary genetics to schistosome epidemiology. Infect Genet Evol 10:433-43
Lotfy, Wael M; Brant, Sara V; Ashmawy, Karam I et al. (2010) A molecular approach for identification of paramphistomes from Africa and Asia. Vet Parasitol 174:234-40
Hanelt, B; Mwangi, I N; Kinuthia, J M et al. (2010) Schistosomes of small mammals from the Lake Victoria Basin, Kenya: new species, familiar species, and implications for schistosomiasis control. Parasitology 137:1109-18
Brant, Sara V; Cohen, Andrew N; Cohen, Andrew N et al. (2010) Cercarial dermatitis transmitted by exotic marine snail. Emerg Infect Dis 16:1357-65
Black, Carla L; Steinauer, Michelle L; Mwinzi, Pauline N M et al. (2009) Impact of intense, longitudinal retreatment with praziquantel on cure rates of schistosomiasis mansoni in a cohort of occupationally exposed adults in western Kenya. Trop Med Int Health 14:450-7
Brant, S V; Loker, E S (2009) Schistosomes in the southwest United States and their potential for causing cercarial dermatitis or 'swimmer's itch'. J Helminthol 83:191-8

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