Ectoparasitic community of the Mahali mole-rat, Cryptomys hottentotus mahali: potential host for vectors of medical importance in South Africa.

BACKGROUND: The endemic rodent family of Bathyergidae in Africa, particularly South Africa, are understudied as reservoirs of diseases of significant medical importance. Considering the diversity and wide distribution of African mole-rats in South Africa, many of these bathyergids could act as carriers of zoonoses. METHODS: The present study assessed the ectoparasite community of the Mahali mole-rat (Cryptomys hottentotus mahali). We aimed to identify possible parasitic arthropods that may infest this mole-rat species and explore host preference, contributions of seasonality, host sex and body mass as well as social class and colony size on ectoparasite assemblage prevalence and abundance. RESULTS: A limited number of ectoparasite species were found on C. h. mahali belonging to two significant taxa: mites (Acari) and fleas, with mites being the most prevalent and abundant. We recorded the presence of X. philoxera, a flea well known as the principal reservoir of plague in the southern African region on the Mahali mole-rats. Only three mite species were collected: Androlaelaps scapularis, Androlaelaps capensis and Laelaps liberiensis. Seasonal peaks in prevalence and abundance of X. philoxera and A. scapularis were observed during summer. Xenopsylla philoxera abundance and A. scapularis loads significantly increased on reproductive mole-rat individuals in comparison to non-reproductive individuals. CONCLUSION: Despite the wide distribution of the subterranean African mole-rats, studies investigating their parasitic fauna remain limited and scarce. This dearth in knowledge raises the concern regarding their potential role as an endemic reservoir for zoonotic diseases. Consequently, additional sampling of their ectoparasitic community throughout their distributional range and research addressing their role as a reservoir for zoonotic diseases in southern Africa are urgently needed.

Complex interactions within the ectoparasite community of the eastern rock sengi (Elephantulus myurus).

Concomitant infection with more than one parasite species is the rule in nature. Since co-infecting parasites are exploiting the same host, interspecific interactions at the infracommunity level are likely. The nature of such interactions can be expected to affect the distribution of parasites within host populations. Intraspecific interactions within the infracommunity are not easily discernible from cross-sectional studies and the focus of most of these studies lies on relationships between endoparasitic micro- and macroparasites. In the current study of the ectoparasite community of wild eastern rock sengis (Elephantulus myurus) we experimentally reduced tick and flea infestations and monitored ectoparasite burdens over the course of three years. We found a number of within-taxon facilitating interactions between tick species that might be the result of decreasing immune responses with increasing tick burden. In contrast, inter-taxon relationships appeared to be dominated by antagonistic relationships likely to be linked to competition over feeding sites. Only one of the observed interspecific interactions was reciprocal. Our experimental manipulation revealed additional antagonistic relationships that cross-sectional studies would not have captured. In addition, we found substantial long-term changes in the sengi ectoparasite community as a result of our experimental manipulation suggesting carry-over effects of our treatment. This study is the first that evaluates interspecific interactions within the entire ectoparasite community exploiting a mammalian host in Africa and highlights the complexity of interspecific interactions within an ectoparasite community.

The Namaqua rock mouse (Micaelamys namaquensis) as a potential reservoir and host of arthropod vectors of diseases of medical and veterinary importance in South Africa.

BACKGROUND: The role of endemic murid rodents as hosts of arthropod vectors of diseases of medical and veterinary significance is well established in the northern hemisphere. In contrast, endemic murids are comparatively understudied as vector hosts in Africa, particularly in South Africa. Considering the great rodent diversity in South Africa, many of which may occur as human commensals, this is unwarranted. METHODS: In the current study we assessed the ectoparasite community of a widespread southern African endemic, the Namaqua rock mouse (Micaelamys namaquensis), that is known to carry Bartonella spp. and may attain pest status. We aimed to identify possible vectors of medical and/or veterinary importance which this species may harbour and explore the contributions of habitat type, season, host sex and body size on ectoparasite prevalence and abundance. RESULTS: Small mammal abundance was substantially lower in grasslands compared to rocky outcrops. Although the small mammal community comprised of different species in the two habitats, M. namaquensis was the most abundant species in both habitat types. From these 23 ectoparasite species from four taxa (fleas, ticks, mites and lice) were collected. However, only one flea (Xenopsylla brasiliensis) and one tick species (Haemaphysalis elliptica) have a high zoonotic potential and have been implicated as vectors for Yersinia pestis and Bartonella spp. and Rickettsia conorii, respectively. The disease status of the most commonly collected tick (Rhipicephalus distinctus) is currently unknown. Only flea burdens differed markedly between habitat types and increased with body size. With the exception of lice, all parasite taxa exhibited seasonal peaks in abundance during spring and summer. CONCLUSION: M. namaquensis is the dominant small mammal species irrespective of habitat type. Despite the great ectoparasite diversity harboured by M. namaquensis, only a small number of these are known as vectors of diseases of medical and/or veterinary importance but occur at high prevalence and/or abundance. This raises concern regarding the potential of this host as an endemic reservoir for zoonotic diseases. Consequently, additional sampling throughout its distributional range and research addressing the role of M. namaquensis as a reservoir for zoonotic diseases in southern Africa is urgently needed.

Parasites of the Nile rat in rural and urban regions of Sudan.

In this investigation on endoparasites (helminths) and ectoparasites of the Nile rat (Arvicanthis niloticus Desmarest, 1822), a total of 220 Nile rats were trapped from different regions of Sudan during the period January 2003-January 2006. Examination of different tissues, identification of parasites, effect of these parasites on the organs, the prevalence and intensity of infestation of the parasites and their relation to the habitat of the host, and sex-related infestations were considered. Results showed that the variation among helminth species was wide, especially in those that are transferred by arthropods. No protozoan parasites or distortion in the infected tissues were observed. No examination for Toxoplasma gondii was carried out. Two species of cestodes (Hymenolepis nana, Hymenolepis diminuta), two genera (Raillietina sp. I, Raillietina sp. II) and one unidentified Hymenolepididae were reported. The most prevalent species of cestodes was Raillietina sp. And for nematodes only one species and one genus were recovered (Monanema nilotica and Streptopharagus sp.). Investigation of skin revealed that 83.8% of rats were infested with one or more of ectoparasites; namely, insects and arachnids. This survey also revealed that fleas and lice were the most common ectoparasites that infested the Nile rat. Synanthropic rodents, particularly those living in close association with man, play a significant role in human health, welfare and economy. It has to be stressed that their arthropod ectoparasites are important vectors of pathogenic microorganisms and they can also be important reservoirs for parasitic zoonoses, like trichinellosis and capillariosis. No doubt, the increase in rodent populations could be followed by an increase in zoonotic diseases (Stojcevic et al. 2004, Durden et al. 2000). Rats and mice (commensal and wild) play an important role in public health, being carriers or reservoirs for infectious diseases that can be transmitted to humans (zoonoses). Xenopsylla cheopis is the most important vector of plague and the rickettsial infection murine typhus (Gratz 1999). Man can also acquire the infection through direct contact with infected animals' tissues (WHO 1987). Arvicanthis niloticus, Mastomys natalensis and Rattus rattus are probably the most important and widespread reservoirs of plague in Kenya: 10 percent of all Rattus rattus tested were found to be positive as compared to 12% of the Arvicanthis niloticus (Gratz 1999).