Cystic Echinococcosis in Algeria: the Role of Cattle as Reservoirs in the Dynamics of Transmission of Echinococcus granulosus to Humans via Dogs.

Abstract

In North Africa, the parasite Echinococcus granulosus is transmitted in a synanthropic cycle evolving mainly between dogs (DH) and sheep (IH), but other animals like cattle are most often found to be more infested with hydatid cysts but their potential role in human contamination via dogs is unknown. The purpose of this study is to assess the prevalence and fertility rates of hydatid cysts in ruminants (cattle and sheep) in two slaughterhouses in central and eastern Algeria. Determining the frequency and fertility of cysts in cattle will assess the degree of involvement of this species, alongside sheep, in the epidemiological cycle of E. granulosus in Algeria. In the present study, prevalence rates were estimated at 4.9% and 10% in slaughtered ruminants, all species combined at the slaughterhouses of El Harrach and Souk Ahras, respectively. The distribution of the prevalence by species indicates higher infestation rates in cattle compared to sheep: 6% vs 3.9% and 37% vs 4.7% in the slaughterhouses of El Harrach and Souk Ahras, respectively. The survey results showed relatively low cyst fertility rates in cattle compared to sheep: 13.8% vs 43.7% and 33.3% vs 71.4% in the two slaughterhouses, El Harrach and Souk Ahras, respectively. The low fertility rate of cysts in cattle can be explained by a poor adaptation of the species, E. granulosus sensu stricto, previously identified by molecular analysis in all samples of hydatid cysts collected from cattle in Algeria. In conclusion, cattle infested with E. granulosus sensu stricto, with low fertility rates, play a minor role in the epidemiology of cystic echinococcosis in Algeria. It is rather an indicator of the persistence of cystic echinococcosis infection in endemic regions.