Ecological and molecular studies on emerging schistosomiasis mansoni in Dhofar Governorate, Sultanate of Oman

Abstract

Summary The recent detection of some cases of autochtonous schistosomiasis mansoni in Dhofar, Oman, prompted a search for the transmission sites. The five field surveys we conducted from November 2000 to February 2002 provided ecological data on schistosomiasis in Dhofar. Twenty‐eight water bodies situated within 8–160 km from Salalah, the largest city of Dhofar and at altitudes of up to 900 m, were surveyed for freshwater snails. Biomphalaria arabica was found in 15 of them. Three sites (Tibraq, Siginitti and Arazat) had Schistosoma infected snails, the first snails shedding cercariae of this parasite ever collected in Oman. The parasite from Dhofar was analysed by Random Amplified Polymorphic DNA comparisons using 11 primers and 167 polymorphic fragments and had 87–88% similarity with Schistosoma mansoni from Guadeloupe, but only 37–38% similarity with S. rodhaini from Burundi. Thus, it is a strain of S. mansoni. During the November 2000 survey, the prosobranch snail Melanoides tuberculata was associated with B. arabica in 10 of the 13 B. arabica sites. Cercariae from other species of Digenea emerged from five of the B. arabica sites, including the three named above. This paper presents the first finding of S. mansoni in the Dhofar Governorate and represents an initial study of the biology of S. mansoni transmission. This parasite and its cycle need further biological and molecular characterization, and the clarification of its epidemiological status in Dhofar Governorate is an urgent task.

Preliminary study on sex-related inflammatory reactions in mice infected with Schistosoma mansoni

“…Indeed, numerous unisexual mollusc infections are found in the field (69% Eppert et al 2002;71% Minchella et al 1995;95% Sire et al 1999). Thus, human unisexual primary infections in the field are highly possible in areas where schistosomiasis is emergent or the transmission rate is low, such as Venezuela (Noya et al 2002) or Oman (Mone´et al 2003). This study constitutes introductory research on the comparative responses of the vertebrate host to male vs female infections.…”

Decline in transmission of schistosomiasis mansoni in Oman

“…Dhofar’s weather is relatively cool and rainy even during the summer (July to September, e.g., in July, mean daily temperature = 26.4 °C, mean rainfall 24.5 mm). Schistosomiasis transmission sites include temporary and permanent, natural and artificial water bodies and riverbeds (wadis) located in a relatively small (80 km × 20 km), hilly area along the coast of the Indian Ocean [15] (Figs. 2 and 3).…”

“…Epidemiological investigations on schistosomiasis, as well as planning of public-health measures to tackle the disease, followed the detection of the first two cases of schistosomiasis, at Sultan Qaboos Hospital in Salalah, in 1979 [15]. Starting in 1982, all water bodies in Dhofar were systematically screened for presence of B. arabica , which revealed presence of the snail in a total of 22 water bodies out of 120, most of which were located in remote mountainous areas, and difficult to reach [17].…”

High Phenotypic Frequencies of Complete Albinism in Wild Populations ofBiomphalaria pfeifferi(Gastropoda: Pulmonata)

“…2) where bilharziasis is reemerging Moné et al, 2003). The area of study forms a wide band 250 km long and 30 km wide (7,500 km 2 ) along the Dhofar coast and includes three drainage basins that empty into the Arabian Sea (Figs.…”