Detection of Rickettsia aeschlimannii and Rickettsia africae in ixodid ticks from Burkina Faso and Somali Region of Ethiopia by new real-time PCR assays

In the framework of cooperation for development projects in Burkina Faso and Ethiopia, we collected ixodid ticks from cattle, small ruminants and camels. We optimized new TaqMan Probe real-time PCR assays to detect Rickettsia aeschlimannii and Rickettsia africae OmpA gene in the collected samples. Rickettsia africae was identified in 75.0% Amblyomma variegatum (95%CI: 56.6-88.5), while R. aeschlimannii in 24.0% Hyalomma truncatum (95%CI: 9.4-45.1) and 50.0% H. rufipes (95%CI: 29.9-70.0) collected from cattle in different provinces throughout Burkina Faso. Ticks from the Libaan zone, Somali Region of Ethiopia, were also infected by R. africae (28.5% prevalence in Amblyomma gemma, 95%CI: 14.7-46.0) and R. aeschlimannii (27.0% H. truncatum, 95%CI: 5.0-62.9; 88.3% H. rufipes, 95%CI: 60.5-99.3). All tested ticks were adults. The developed diagnostic tools were highly sensitive and enabled us to rapidly classify R. aeschlimannii and R. africae, which were identified in Burkina Faso and in the Somali Region of Ethiopia for the first time. Further studies are needed to assess the zoonotic risk and prevalence of infection in local human populations, who have high contact rates with ticks and their animal hosts.

Ticks and tick-borne pathogens in livestock from nomadic herds in the Somali Region, Ethiopia

Between May 2006 and January 2007, blood samples and ticks were randomly collected from 220 nomadic animals from Filtu and Dollo Odo districts, Libaan zone, in the Somali Region of Ethiopia. Overall, 81.5% cattle, 98.2% camels, 53.4% goats and 61.1% sheep were infested by ixodid ticks. Collected ticks (n = 1,036) were identified as Rhipicephalus pulchellus (40.1%), R. pravus (25.8%), Amblyomma gemma (9.4%), Hyalomma rufipes (13.3%), H. truncatum (2.8%), H. impeltatum (1.2%) and H. dromedarii (0.5%); immature stages (6.1%) belonged to the genera Rhipicephalus and Amblyomma. Tick infestation burden was evaluated by the Tick Abundance Score method on 57 animals from Dollo Odo in August 2006, and it was significantly higher in cattle and camels than in small ruminants (p < 0.001). Reverse Line Blot Hybridisation was applied to detect Theileria, Babesia, Ehrlichia and Anaplasma spp. Five out of 50 blood samples from Filtu, four from cattle and, surprisingly, one from a camel, were positive for Theileria mutans and two from cattle for T. velifera. Adult ticks (n = 104) from both districts were tested and A. gemma from cattle were positive to T. velifera (1) and Ehrlichia ruminantium (5 samples). Positive E. ruminantium samples were also tested by PCR targeting pCS20 and 16S rRNA genes and submitted to DNA sequencing. The phylogenetic reconstruction of pCS20 fragment showed the presence of the Somali region sequences in the East-South African group. Our results are the first available on ticks and selected tick-borne diseases from the Somali region of Ethiopia and could be used as preliminary information for planning sustainable control strategies for tick and tick-borne pathogens in the study area and in neighbouring areas with similar socio-ecological features.

Trichinella britovi etiological agent of sylvatic trichinellosis in the Republic of Guinea (West Africa) and a re-evaluation of geographical distribution for encapsulated species in Africa

In West Africa, Trichinella infection was documented in humans and animals from Senegal in the 1960s, and the biological characters of one isolate showed a lower infectivity to domestic pigs and rodents when compared with that of a Trichinella spiralis pig isolate from Europe. To identify the Trichinella species present in West Africa, a survey was conducted in a total of 160 wild animals in the Republic of Guinea. Three Viverridae, one true civet (Viverra civetta) and two African palm civets (Nandinia binotata) from the Fouta Djallon Massif, Pilimini Subprefecture, were found positive by artificial digestion of muscle samples. Trichinella larvae from these three viverrids were identified as Trichinella britovi and no difference was detected in three examined sequences from these African isolates and the reference strain of T. britovi from Europe, indicating common ancestry, an historically continuous geographic distribution, and recent isolation for African and European populations. The detection of T. britovi in West Africa modifies our knowledge about the distribution of encapsulated species of Trichinella in Africa. Thus, Trichinella nelsoni is now considered to have a distribution limited to the Eastern part of the Afrotropical region from Kenya to South Africa. This provides a plausible explanation for the presence of Trichinella T8 in Namibia and South Africa, and further suggests that T. britovi could be the Trichinella species circulating among wild animals of Northern Africa.

Detection of Babesia caballi in Amblyomma variegatum ticks (Acari: Ixodidae) collected from cattle in the Republic of Guinea

A reverse line blot hybridisation (RLB) assay was applied to screen Amblyomma variegatum adult ticks (n = 504) collected from N'Dama cattle in the Republic of Guinea. In a PCR, the V1 hypervariable region of the 16S ribosomal RNA (rRNA) gene was amplified with a set of primers unique for species of the genera Anaplasma and Ehrlichia, and the V4 hypervariable region of the 18S rRNA gene was amplified with primers specific for members of the genera Theileria and Babesia. Amplified PCR products from A. variegatum ticks were hybridised onto a membrane, to which oligonucleotide probes species-specific for Ehrlichia/Anaplasma and Theileria/Babesia parasites were covalently linked. No pathogens belonging to Ehrlichia/Anaplasma species were found, while 10 DNA samples resulted positive for Babesia caballi and 5 samples for Theileria velifera. This is the first report of B. caballi in A. variegatum ticks. One of the B. caballi positive samples was sequenced. This new strain (BcabGuinea) showed a 97% similarity to the Z15104 B. caballi GenBank sequence.

[Prevalence of Bartonella henselae in stray and domestic cats in different Italian areas: evaluation of the potential risk of transmission of Bartonella to humans]

Bartonella henselae is the major etiological agent of Cat Scratch Disease in humans. Cats act as the natural reservoir of B. henselae and can transmit the infection to humans by bite or scratch. The diffusion of B. henselae was evaluated by seroprevalence and bacteremic status in different stray cat populations located in nine areas of Northern Italy. A total of 1585 cats were tested by blood culture and 361 (23%) resulted bacteremic; 1416 out off 1585 cats were also tested for Bartonella henselae antibodies and 553 (39%) resulted seropositive. The molecular typing of the isolates showed that 26% of bacteremic cats were infected with B. henselae type I, 52% with B. henselae type II, 16% were co-infected with both and 5% infected with B. Clarridgeiae. Moreover 165 domestic cats were tested by blood culture and serological test (IFA test cut-off: 1:64). 35 cats (21%) resulted bacteremic and 49 (43.5%) were seropositive. The molecular typing of the Bartonella isolates of the domestic cats showed that 45% of bacteremic cats were infected with B. henselae type I, 36.5% with B. henselae type II, 12% were coinfected with both and 6% infected with B. Clarridgeiae. For a completely evaluation of health status of the cat for B. henselae infection, the authors suggest both blood culture and serological tests. Nevertheless a nonbacteremic cat with positive serology result should be reevaluated for possible recurrent bacteremia.

Acarological risk of exposure to agents of tick-borne zoonoses in the first recognized Italian focus of Lyme borreliosis

Acarological risk was calculated as the probability of encountering at least one host-seeking Ixodes ricinus tick infected by the pathogen Borrelia burgdorferi sensu lato, in 100 m transects in the province of Genoa, Italy. The seasonal pattern of I. ricinus was studied using generalized estimating equations (GEE) with negative binomial error, to consider overdispersion of tick counts and repeated sampling of the same dragging sites from April 1998 to March 1999. Prevalence of infection by B. burgdorferi s.l. was evaluated by PCR and hybridization with genospecies-specific probes. Acarological risk (R) peaked in April (R = 0.2, 95% CI 0.13-0.26) and November (R = 0.29, 95% CI 0.10-0.46). Borrelia garinii and B. valaisiana were the most common genospecies at our study site suggesting a major role of birds as reservoirs. DNA from Anaplasma phagocytophilum, the agent of granulocytic ehrlichiosis in humans and animals, was amplified from an adult I. ricinus.

Antibodies to Neospora caninum in wild animals from Kenya, East Africa

The prevalence of antibodies to Neospora caninum was examined in six wild Artiodactyla species, and in five wild Carnivora species from Kenya. Blood sera (104 wild ungulates from Marula Estates (MEs), and 31 wild carnivores from Masai-Mara reserve and from other wildlife areas in northern and Southern Kenya), were screened using a Neospora agglutination test (NAT), with a twofold dilution (1:40-1:320 titres). Presence of NAT antibodies to N. caninun is reported here for the first time in zebra (Equus burchelli), eland (Taurotragus oryx), African buffalo (Syncerus caffer), Thompson gazelle (Gazella thompsoni), impala (Aepyceros melampus), warthog (Phacochoerus aethiopicus), spotted hyena (Crocuta crocuta) and in free-ranging cheetah (Acinonyx jubatus). At 1:80 dilution, prevalence was 61.5% in eland, 58.5% in zebra, 19.2% in Thompson gazelle, 33.3% in warthog, 50% in African buffalo, 30% in lion (Panthera leo), 20% in cheetah, and 33.3% in spotted hyena. Antibodies up to 1:320 titre were detected in eland (38.4%), zebra (19.5%), Thompson gazelle (3.8%) and lion (5%). Amongst herbivores, sero-prevalence was significantly (P<0.05) higher, at all dilutions, in "grazer/digger" species (e.g. eland and zebra) than in non-"grazer/digger" species (e.g. impala and Thompson gazelle). No antibodies to N. caninum were found in two leopards (Panthera pardus) and one serval (Felis serval). Our results indicates a steady presence of N. caninum in wild mammals from Kenya. The hypothesis of a sylvatic cycle of N. caninum could be suggested, but more data are needed to verify the hypothesis, as to evaluate the role of N. caninum infection on the dynamics of wild animals population in the study area.

Dermatophilosis of Alpine Chamois (Rupicapra rupicapra) in Italy

A proliferative dermatitis similar to the condition generally referred to as strawberry footrot was observed in two Alpine chamois (Rupicapra rupicapra) from Eastern Alps, Italy. Branching septated filaments and packets of PAS-positive coccoid organisms were observed in histological sections of the affected skin. The actinomycete, Dermatophilus congolensis, was isolated from crusted lesions in one chamois. As wild ruminants are presumed to be a reservoir of infection in the Alpine area, the authors discuss the potential role of chamois in the epidemiology of dermatophilosis.

Pentastomes (Pentastomida, Armillifer armillatus Wyman, 1848) in snakes from Zambia

Twenty-three snakes, belonging to eight different species, were collected from rural areas of Zambia and inspected for the presence of pentastomes. Pentastomid parasites were found in four snakes: one African rock python (Python sebae), one puff adder (Bitis arietans) and two Mozambique spitting cobras (Naja mossambica) were infested with a small number of Armillifer armillatus, respectively five, two and one adult parasites. As humans can be incidental/intermediate hosts for reptilian pentastomes, the zoonotic potential of these parasites, especially in tropical countries, is discussed.

Trichinella nelsoni in carnivores from the Serengeti ecosystem, Tanzania

A survey of trichinellosis among sylvatic carnivore mammals from the Serengeti ecosystem (Tanzania) demonstrated the presence of Trichinella nelsoni in 5 of 9 species examined. Muscle samples were collected from carcasses of 56 carnivores from 1993 to 1995 and frozen before transport and examination. Following artificial digestion of the samples, collected larvae were analyzed by the random amplified polymorphic DNA technique. Trichinella nelsoni was identified in 1 bat-eared fox (Otocyon megalotis), 1 cheetah (Acinonyx jubatus), 1 leopard (Panthera pardus), 3 lions (Panthera leo), and 3 spotted hyenas (Crocuta crocuta). The numbers of bat-eared foxes (6), cheetahs (5), and leopards (3) examined were too small to reveal the roles of these carnivore species in the ecology of T. nelsoni. The numbers of lions and spotted hyenas examined, with a prevalence of 12% and 23%, respectively, suggest that these species may be reservoirs of T. nelsoni in the area under study.

Ticks (Acarina: Ixodidae) of reptiles from central, Lusaka and southern provinces of Zambia

During the period 1988-1991, reptiles (23 snakes, 36 tortoises, 25 chameleons and 2 monitor lizards) from Central, Lusaka and Southern Provinces of Zambia were caught and checked for ticks. Only 2 snakes, respectively one Python sebae (Gmelin, 1789) and one Bitis arietans (Merrem, 1820), 8 tortoises, respectively seven Geochelone pardalis (Bell, 1828) and one Kinixys belliana (Gray, 1831) were found infested with a small number of ticks: nymphs and adults of Aponomma latum (Koch, 1844) and Amblyomma marmoreum Koch, 1844. Ticks were not observed on chameleons Chamaeleo dilepis (Leach, 1819) and monitor lizards Varanus niloticus (Linneo, 1758). The author makes some observations about the role and the effects of ticks on reptiles and discusses the present findings, comparing the data provided by other authors.

Sero-prevalences of selected cattle diseases in the Kafue flats of Zambia

Sera from five traditionally managed herds grazing in the Kafue flats were tested for antibodies to bovine viral diarrhoea-mucosal disease (BVD-MD), parainfluenza 3 (PI3), infectious bovine rhinotracheitis-infectious pustular vulvovaginitis (IBR-IPV), bovine adenovirus 3 (BAV3) and Bluetongue (BT). The sero-prevalences of the first four diseases were respectively 76.2, 94.4, 42.1 and 87.4%. Five samples (2.3%) gave doubtful reactions for BT. Prevalences of 28.5% for brucellosis, 14% for Rift Valley fever (RFV), 0.9% for Q fever and 11.2% for chlamydiosis were also recorded. Significantly higher values for BVD-MD (p less than 0.005), IBR-IPV (p less than 0.01) and brucellosis (p less than 0.05) were found in animals over 1 year of age. No differences were recorded between herds or between male and female animals. The high concentration of wild and domestic ruminants grazing together in the flood plains during the dry season may be a major determinant of the high values observed. Traditional farmers, slaughterhouse workers and other people involved in livestock production are particularly at risk of contracting brucellosis and RVF because of the high prevalences in cattle and local habits favourable to their transmission.

Experimental transmission of a sarcosporidian from Alpine ibex to domestic sheep and goats

Sporocysts of Sarcocystis sp. from dogs fed with ibex meat were orally inoculated into kids and lambs. Three kids, given 4 x 10(6) and 4 x 10(4) sporocysts, respectively, died from acute sarcocystosis. Schizonts, though found in all the tissues of these kids, were particularly numerous in the kidneys, brain and spinal cord. Another three kids inoculated with 5 x 10(3) sporocysts and two lambs, inoculated with 1 x 10(6) and 5 x 10(3) sporocysts, respectively, showed no clinical signs and were sacrificed between 111 and 130 days after infection. Mature sarcocysts were found both in the heart and striated muscles of these animals. No parasitic stage was found in two kids and two lambs used as uninoculated controls. Biological differences between Sarcocystis sp. from ibex and the other sarcosporidians with a canine-caprine or canine-ovine cycle are stressed.