Cystic echinococcosis (Echinococcus granulosus sensu lato infection) in Tunisia, a One Health perspective for a future control programme

Abstract

The emergence of pandemics with dramatic consequences for human health has obscured endemic diseases that continue to pose a problem for human and animal health in several regions of the world. Among these diseases, cystic echinococcosis, a zoonotic parasitic infection caused by a group of cestodes, Echinococcus granulosus sensu lato, remains a real human and animal health problem in several regions of the world, including the Mediterranean Basin. Despite the implementation of a number of governmental control programmes using several tools (dog treatment, meat inspection, etc.), this infection is still highly prevalent in North Africa. Here we present a review of the epidemiology of cystic echinococcosis in Tunisia, an analysis of the constraints limiting the effectiveness of the control programmes implemented, and finally argue for the use of the One Health framework to improve the effectiveness of future programmes.

Keywords: Cestode; Constraint; Control; Echinococcus granulosus; One Health; Slaughterhouse; Tunisia.

Figure 1

A heavily infected ewe liver, called “egg basket” locally.

Figure 2

Restaurant preparing grilled meat with non-controlled lamb meat.

Figure 3

Seized offal in a Tunisian slaughterhouse that is often thrown on the ground.

Figure 4

General epidemiology of the three main zoonotic diseases involving dogs in Tunisia: cystic echinococcosis (Echinococcus granulosus infection), leishmaniosis (Leishmania infantum infection) and rabies. (a) Transmission routes of Echinococcus spp., Leishmania spp. and rabies in Tunisia (domestic and peri-domestic and wild socio-ecosystems) and the disciplines involved in their control. The yellow circle limits the space of domestic and peri-domestic transmission, the green circle the space for wildlife transmission. The figure shows how different disciplines (in brown) articulate and can contribute to knowledge and control of these three zoonotic diseases involving dogs. (b) Based on the geography of Tunisia (map after [18]), we hypothesise the existence of different patterns of transmission of the three zoonotic diseases involving dogs with “north–south “ and “urban–wild” gradients. The size of each circle is proportional to its importance in the transmission system. Along each gradient, the contributions of hosts and pathogens and the weights of the driving factors vary, possibly leading to different transmission patterns (numbered 1, 2, ..., n − 1, n).

Figure 5

General patterns of transmission of Echinococcus spp. and control points in Tunisia. In red, the parasite route; in blue, the hosts involved and behaviours favouring transmission (the size of the characters indicates their presumed importance in transmission); in green, human actions that may modulate transmission.