The spatio‐temporal distribution of a rodent reservoir host of cutaneous leishmaniasis

Abstract

Summary1. The rodent Psammomys obesus is the main reservoir host for Leishmania major, the causative agent of cutaneous leishmaniasis in Tunisia, much of North Africa and mid-western Asia. An understanding of the population dynamics of this rodent is essential to establish a preventive control strategy based on the early prediction of rodent outbreaks. 2. The study of P. obesus dynamics at a regional scale requires index-based sampling. Rodent numbers were monitored twice per year at the beginning and end of the breeding season, using transects around the Sidi Bouzid region in central Tunisia. 3. Two di erent types of dynamics occurred in two drainage basins. Rodents living in the northern basin were at low density and those living in the southern basin were at high density. 4. At the scale of a plot, occupied burrows were generally associated with the presence of three Chenopodiaceae: Arthrocnemum glaucum, Salsola tetrandra and Suñda fruticosa, rarely in monospeci®c formations. However, in dry periods, occupied burrows drifted to A. glaucum formation linked with high moisture and salinity of the soil (w 2 MacNemar 6Á26). 5. The risk of a P. obesus outbreak can be assessed by a simultaneous knowledge of¯ooding regimes in the drainage basins, the distribution of halophytic plant formations, and the progressive movements of the rodents as drying out proceeds. The transect indices of rodents are easily repeatable, economical and would be applicable in other developing countries where cutaneous leishmaniasis occurs. 6. This work illustrates that simple ecological methods can assist the assessment of spatial and temporal components of epidemiological risk such as the proximity between rodent colonies and human habitats at the time of outbreaks.

Extension de Leishmania major au nord de l’Algérie

“…Cela dénote une remarquable adaptation écologique chez ce rongeur. Petter rapporte que cette espèce est exclusivement confinée aux réseaux hydrographiques sahariens [23], alors que Fichet-Calvet note que P. obesus peut survivre en dehors de son territoire, notamment en période de stress hydrique, en colonisant des surfaces riches en plantes de la famille des Chénopodiacées, loin des Chotts [13,18]. Cette présence dans le sous-bassin d'El M'hir est liée à des facteurs édaphiques particuliers, notamment la présence de salinité d'origine géologique (marnes gypsosalines).…”

Urban Transmission of American Cutaneous Leishmaniasis in Argentina: Spatial Analysis Study

“…The high OR values for the clusters corresponding to pediatric cases located in the southern and eastern areas of the city might be related to increases in periurban reservoirs as a source of parasites and their overlap with vector distribution in borders having transitional landscape of urban-rural or urbanresidual vegetation ( Figure 5 ). 22,43 The association between ACL prevalence and the basic unstatisfied needs index could be related to peripheral location of settlements with impoverished populations, in which geographic proximity to vector exposure is higher. Among those neighborhoods with clusters with radius = 0, these results indicate that those neighborhoods are entities with particular physical, cultural, and/or socioeconomic characteristics that pose a significant risk for infection.…”

Leishmania Major Infection Among Psammomys Obesus and Meriones Shawi: Reservoirs of Zoonotic Cutaneous Leishmaniasis in Sidi Bouzid (Central Tunisia)

“…This vector frequently used rodents' burrows for daytime resting and breeding (Helal et al 1987, Esseghir et al 1993. Many ecological studies of the reservoir hosts identified three rodent species carrying L. major: Psammomys obesus Cretzschmar 1828 with a major part in amplifying the transmission, Meriones shawi Duvernoy 1842 and Meriones libycus Lichtenstein 1823 with a role to propagate the parasite between P. obesus colonies because of their common migration, thus increasing the distribution of the parasite (Bouratbine Balma 1988, Fichet-Calvet et al 2000. P. obesus, the fat sand rat, is distributed through the semidesert on the northern fringe of the Sahara, from Mauritania through Morocco, Algeria, Tunisia, Libya, Egypt, Palestine, Jordan, Saudi Arabia, and Syria.…”