Protozoan and bacterial pathogens in tick salivary glands in wild and domestic animal environments in South Africa.

A total of 7364 ticks belonging to 13 species was collected from 64 game animals (belonging to 11 species) and from 64 livestock animals (cattle and sheep) living in close vicinity at 6 localities in 3 South African Provinces (Free State, Mpumalanga, and Limpopo). The geographic distribution of all tick species was congruent with the literature except for Haemaphysalis silacea. From each infested host, a maximum of 10 males and 10 females of each tick species were dissected to isolate the salivary glands. Salivary glands were screened for tick-borne pathogens using polymerase chain reaction followed by reverse line blotting and sequencing. This approach allowed us to evaluate the exposure of wild and domestic hosts to tick-borne pathogens in their respective environments. Among the 2117 examined ticks, 329 (15.5%), belonging to 8 species, were infected and harboured 397 infections. Among those, 57.7% were identified to species level and were assigned to 23 pathogen species of the genera Babesia, Theileria, Anaplasma, and Ehrlichia. In 3 out of 6 localities, salivary glands from ticks infesting wild ruminants displayed significantly higher infection prevalence and pathogen mean density than salivary glands from ticks infesting livestock animals. Four piroplasm species [Theileria bicornis, Babesia sp. (sable), Theileria sp. (giraffe), and Theileria sp. (kudu)] were detected for the first time in ticks. The tick species Rhipicephalus evertsi evertsi, Rhipicephalus (Boophilus) decoloratus, Hyalomma rufipes, Rhipicephalus appendiculatus, and Amblyomma hebraeum were associated with a broader pathogen range than previously known, and thus new vector-pathogen combinations are described. In addition, previously unknown coinfection patterns in tick salivary glands are reported.

Tick-borne pathogens in the blood of wild and domestic ungulates in South Africa: interplay of game and livestock.

We screened for tick-borne pathogens blood samples from 181 wild and domestic ungulates belonging to 18 host species in 4 South African Provinces. Polymerase chain reaction followed by reverse line blotting and sequencing allowed detecting 16 tick-borne pathogen species belonging to the genera Babesia, Theileria, Anaplasma, and Ehrlichia. Ten pathogen species were involved in 29 new host-pathogen combinations. Most infections (77.9%) involved more than one pathogen species. Principal component analysis (PCA) assigned the 163 infections, identified to species level, to 4 groups. Three groups were associated with sheep, cattle, and horse and their respective wild counterparts. Each group was characterised by high homogeneity in pathogen assemblage and host phylogenetic status. These groups characterised the most privileged transmission routes between and among wild and domestic ungulates. The 4th group showed high heterogeneity in pathogen assemblage and host phylogenetic status. This group seems to indicate frequent spill over events in impala of pathogens that usually circulate among cattle- or sheep-related species. Within 6 localities, we sampled an equal number of wild and domestic animals (n=128). On this dataset once having controlled for the significant variation among localities, the infection prevalence and intensity of infection did not differ significantly between wild and domestic hosts. This suggests that both animal types, domestic and wild hosts, could act as evenly efficient sources of infection for themselves and for each other. Overall, this study shed new light on the pathogen circulation naturally achieved at the interplay between wild and domestic ungulates.

Ticks and tick-borne pathogens from wildlife in the Free State Province, South Africa.

Eight ixodid tick species, associated with 59 free-ranging mammals belonging to 10 species, were collected at five different localities in the Free State Province, South Africa. Four of the study areas were nature reserves (Willem Pretorius, Sandveld, Tussen-die-Riviere, and Soetdoring), and one site was a private farm located in Senekal district. The collection was performed from March 2006 until June 2006. Ticks (n=569) and tissues from animals (n=52) were analyzed by polymerase chain reaction, reverse line blot, and sequencing for various tick-borne pathogens belonging to the genera Babesia, Theileria, Anaplasma, and Ehrlichia. Rhipicephalus (Boophilus) microplus, the known vector of Babesia bovis responsible for Asiatic redwater in South Africa, was found for the first time in the Free State Province. Rhipicephalus warburtoni [corrected] also was collected in areas in the Free State where it has not been previously described. Anaplasma marginale was detected for the first time in a gemsbok (Oryx gazella gazella). Gene sequences recovered in this study were 98-100% homologous with GenBank sequences for Anaplasma bovis, Theileria separata, and Theileria sp. Malelane sable antelope.

An update on human bartonelloses.

The data available on Bartonella species has increased rapidly in the last decade with 12 new species and subspecies being described and bartonellas being found to be associated with an increasing spectrum of clinical syndromes in immunocompetent and immunocompromised patients. In addition B. weissii is found in cats. This rapid expansion of knowledge has come about with the development of new culture and molecular biology techniques to isolate and identify the organisms. Much of the information on the bartonellas and the emerging infectious diseases they cause has been derived from the USA and Europe although there is growing evidence that the organisms may be important pathogens in other regions including southern Africa. In this review we describe the bacteriology, epidemiology, clinical and laboratory signs, diagnosis and treatment of bartonella infections and the most recent data on bartonellas in southern Africa.

An update on human ehrlichioses.

Recent applications of molecular approaches to research on ehrlichias have significantly advanced our understanding of the organisms and the diseases they cause. Most of this research has taken place in the USA and Europe where three new species of Ehrlichia that are pathogenic in people have been discovered in the last 15 years. There is still, however, little information on ehrlichia in Africa although limited studies have shown the organisms may be important pathogens on the continent. To raise awareness of ehrlichias amongst health workers, in this review we describe the Ehrlichia spp. that are human pathogens and the signs, diagnosis and treatment of the diseases they cause.

Isolation of Bartonella henselae from a serologically negative cat in Bloemfontein, South Africa.

Sera collected from apparently healthy 6-12-month-old cats (n = 31) presented to the Society for the Prevention of Cruelty to Animals Veterinary Clinic in Bloemfontein for neutering were tested for antibodies reactive to Bartonella henselae (Houston-1 strain) by indirect fluorescent antibody testing. Whole blood collected from the cats was used in isolation experiments and subsequent identification of Bartonella species was based on comparison of the nucleotide base sequence of polymerase chain reaction-amplified citrate synthase gene fragments. While none of the cats had antibodies reactive with B. henselae at titres > or =1/64, an organism with a partial citrate synthase gene sequence identical to that of B. henselae (Houston-1) was isolated from 1 cat.

Serological survey for antibodies reactive with Ehrlichia canis and E. chaffeensis in dogs from the Bloemfontein area, South Africa.

Sera from 161 dogs in the Bloemfontein area in South Africa were tested for the presence of antibodies reactive with Ehrlichia canis and E. chaffeensis by indirect fluorescent antibody testing. Overall, 68 (42%) of the dogs had significant antibody titres (> or = 1/64) against E. canis and 61 (38%) had significant titres (> or = 1/64) against E. chaffeensis. Seven (11%) dogs had higher titres to E. chaffeensis than E. canis (1/2048 and 1/1024 (2 dogs); 1/1024 and 1/512 (2 dogs); 1/2048 and 1/512; 1/512 and 1/256 and 1/512 and < 1/64, respectively). The remaining seropositive dogs had equal (n = 26; 42%) or 2-(n = 17; 25%), 3-(n = 13; 2%) or 4-fold (n = 5; 7%) higher titres against E. canis. Dogs from economically depressed, high-density suburbs (60/112; 48%) had significantly higher prevalences of antibodies against E. canis than those from more affluent, low-density suburbs (8/49; 14%) (chi 2 = 19.38, p < 0.001). Higher titres to E. chaffeensis than E. canis were found in dogs from affluent, low-density suburbs (3/49) and in dogs from economically depressed, high-density suburbs (4/112).

HTLV-I infection in the Free State region of South Africa: a sero-epidemiologic study.

Human T-lymphotropic virus type I (HTLV-1) is associated with tropical spastic paraparesis (TSP) and adult T-cell leukemia/lymphoma. HTLV-I infection is endemic in certain parts of the Natal/KwaZulu region of South Africa. No studies on the seroprevalence of HTLV-I infection in the Free State (FS) have been published. This study was designed to determine the prevalence of HTLV-I antibodies among different patient groups in the FS. Sera from 863 patients were analyzed. There were: 178 asymptomatic rural Blacks, 200 asymptomatic urban Blacks, 50 asymptomatic Whites, 60 patients with spastic myelopathy, 70 patients with other neurologic disorders, 12 patients with T-cell haematologic malignancies and 293 human immunodeficiency virus (HIV) seropositive patients. Sera were tested for the presence of HTLV-I/II antibodies using an enzyme linked immunosorbent assay (ELISA). Positive results were confirmed using a modified Western blot assay. None of the asymptomatic Whites were HTLV-I antibody positive (95 pc confidence interval (CI): 0 to 7 pc), while 2 pc (95 CI: 0.5 to 5 pc) of asymptomatic urban Blacks and 1.1 pc (95 pc CI: 0.14 to 4 pc) of asymptomatic rural Blacks had HTLV-I antibodies. Of the group of patients with spastic myelopathy 33.3 pc (95 pc CI: 21.7 to 46.7 pc had HTLV-I antibodies, while none of the patients with T-cell haematologic malignancies (95 pc CI: 0 to 26.5 pc) or other neurologic disorders (95 pc CI: 0 to 5 pc) had HTLV-I antibodies. Of the HIV seropositive patients 6.1 (95 pc CI: 4 to 9.5) were co-infected with HTLV-I. HTLV-I infection is present in the Free State. It is strongly associated with spastic myelopathy in this region. HIV seropositive patients have a high rate of HTLV-I co-infection.

PGM3 locus and its genetic polymorphism in lymphocytes of the pig.

PGM3 activity was investigated by means of horizontal starch gel electrophoresis. In the pig of the German Landrace three different phenotypes have been recognized: F, S and FS. Family studies suggest the occurrence of at least two alleles--PGM3F and the PGM3S at an autosomal locus.

Investigations of red cell glyoxalase in recombinant families.

The polymorphism of the red cell glyoxalase (GLO), which has recently been found to be linked with the major histocompatibility complex (HLA) in man, was investigated in a number of selected families showing various recombinations between HLA-A, HLA-B and the third locus of the phosphoglucomutase (PGM3). In two families with a recombination between HLA-A and HLA-B, the GLO allele travels with the HLA-B locus fragment of the chromosome, indicating that GLO is located on the side of the HLA-B locus. In other families, recombinations occurred between HLA-A and B on one side and GLO and PGM3 on the other side, demonstrating that GLO and PGM3 are located on the same side of HLA. Other recombinations separated PGM3 from GLO so that it can be assumed that GLO is located between HLA-B and PGM3. Thus the immunogenetic linkage group on human chromosome C6 has been increased by yet another outside marker gene to include now the following genes in this order: HLA-A--HLA-C--HLA-B--Bf--HLA-D--GLO--PGM3.

PGM3 locus and its genetic polymorphism in leucocytes of goats.

PGM3 activity was investigated in 150 'Boerbok' goats and 132 Angora goats by means of horizontal starch gel electrophoresis. In 'Boerbok' goats no polymorphism was found. In Angora goats three different phenotypes have been recognized: F, S, and FS. The results suggest the occurrence of two common alleles: PGM3-F and PGM3-S at an autosomal locus with frequencies of 0.6176 and 0.3824, respectively.

Preliminary evidence for a fourth phosphoglucomutase (PGM) locus in the dog.

The PGM polymorphisms were investigated in starch gel electrophoresis in a total of 34 dogs. After prolonged incubation, a zone located 5-6 cm anodal to PGM3 was found in which two clear bands were identified. Two dogs had only the faster band, and two dogs had only the slower band. This provides preliminary evidence for the existence of a fourth PGM locus in dogs. A series of exclusion experiments indicates that the newly found bands contain PGM activity.