Parasites of domestic and wild animals in South Africa. XX. Arthropod parasites of the Cape mountain zebra (Equus zebra zebra)

The arthropod parasite burdens of 14 Cape mountain zebra (Equus zebra zebra), shot for survey purposes in the Mountain Zebra National Park in the eastern Cape Province, were determined. Three species of Gasterophilus larvae and 9 ixodid tick species were recovered. Larvae of Gasterophilus pecorum were the most numerous of the fly larvae recovered and Margaropus winthemi was the most abundant tick. Two horses examined in the park were infested with 3 species of Gasterophilus larvae and 7 species of ixodid ticks.     

In vitro isolation of equine piroplasms derived from Cape Mountain zebra (Equus zebra zebra) in South Africa

Twenty blood samples of zebras (Equus zebra zebra) from the Karoo National Park and the Bontebok National Park in South Africa, all seropositive for Theileria equi, were subjected to in vitro culture to identify carrier animals and to isolate the parasites. Sixteen animals had a detectable parasitaemia in Giemsa-stained blood smears examined before culture initiation, the remaining four animals were identified as T. equi carriers by in vitro culture. Cultures were initiated either in an oxygen-reduced gas mixture or in a 5% CO2-in-air atmosphere. Out of the 20 blood samples, 12 cultures of T. equi and two cultures of T. equi mixed with Babesia caballi were established. None of the four animals seropositive for B. caballi could be identified as carrier animals, whereas two seronegative samples became culture-positive for B. caballi.     

Descriptive study of an outbreak of equine sarcoid in a population of Cape mountain zebra (Equus zebra zebra) in the Gariep Nature Reserve

An outbreak of equine sarcoid occurred in a population of Cape mountain zebra (Equus zebra zebra) at the Gariep Nature Reserve located in the southern Free State Province of South Africa in 1996. The course of the outbreak during 1996 to 2003 is described. During this period the average population size was 69 animals. Initially (1996) all affected animals were removed from the population. New cases continued to manifest and the incidence varied between 4.6% and 17.6%. Prevalence reached 24.7% in 2002. No sexual predilection was noticed in the 39 recorded cases. Of the affected individuals, 64% had a single lesion and no animal had more than 4 lesions. In males, the majority of lesions occurred in the inguinal area (55.17%), whereas in females they mostly occurred on the head and neck (41.38%). Lesions can increase 260% in size annually and may impede movement.     

Descriptions of incisors of known-age Cape mountain zebras, Equus zebra zebra, from the Mountain Zebra National Park

Twelve sets of incisors of Cape mountain zebras, 9 of which were from known-age individuals ranging in age from 11 months to 19 years, from the Mountain Zebra National Park, are described and depicted to illustrate not only the eruption and replacement sequence, but also the changes with increasing age in the configuration of the occlusal surfaces and of the infudibulum. Infundibula persist in maxillary incisors longer than in mandibular incisors. Shallow infundibula were still present in the maxillary incisors of a 19-year-old mare at least 4 years later than in plains zebras, E. burchelli, from the Kruger National Park. The physiological life span of Cape mountain zebras appears to be at least 26 years.     

Arthropod parasites of Hartmann's mountain zebra, Equus zebra hartmannae, in South West Africa/Namibia

Twelve Hartmann's mountain zebra, Equus zebra hartmannae, were shot for arthropod parasite recovery during the period June 1980-June 1981 on a farm in the Khomas Hochland region of South West Africa/Namibia. Four species of Gasterophilus larvae, 1 species of Rhinoestrus larvae and 3 ixodid tick species were recovered. The seasonal prevalence of the Gasterophilus species larvae and of Rhipicephalus evertsi mimeticus was determined. Three horses examined on the same farm were infested with larvae of 2 Gasterophilus species and with the same ixodid tick species as the zebras.     

Standing sedation in captive zebra (Equus grevyi and Equus burchellii)

Nine Grevy's zebras (Equus grevyi) and three Burchell's zebras (Equus burchellii) were immobilized in a standing position a total of 70 times for minor, nonpainful procedures over a 9-yr period. Standing sedation was successfully obtained with a combination of detomidine and butorphanol on 47 occasions (67.1%). Detomidine i.m. (median 0.10 mg/kg; range: 0.07-0.21) was administered by dart, followed 10 min later by butorphanol i.m. (median 0.13 mg/kg; range 0.04-0.24). The dosages were varied depending on the initial demeanor of the animal. On 23 occasions (32.9%), small amounts of etorphine (median 2.5 microg/kg; range 1.1-12.3 microg/kg) plus acepromazine (median 10 microg/kg; range 4.4-50 microg/kg) (as in Large Animal-Immobilon) had to be administered i.m. to gain sufficient sedation. In these latter cases, the animals were either excited or known for their aggressive character. The zebras were sufficiently immobilized for the length of most procedures (<45 min) without supplementation. At the end of the procedure, the animals were given atipamezole (2 mg per 1 mg detomidine used) and naltrexone (0.1 mg/kg) to reverse the sedative effects, irrespective of whether etorphine was used or not. Standing sedation, using the combination of the alpha-2 agonist detomidine and the partial agonist-antagonist opioid butorphanol (in some cases supplemented with etorphine + acepromazine), proved to be a very efficacious and safe method to be used in zebras under zoo conditions for short-lasting, nonpainful procedures.     

Pathology and immunohistochemistry of papillomavirus-associated cutaneous lesions in Cape mountain zebra, giraffe, sable antelope and African buffalo in South Africa

Skin lesions associated with papillomaviruses have been reported in many animal species and man. Bovine papillomavirus (BVP) affects mainly the epidermis, but also the dermis in several species including bovine, the best-known example being equine sarcoid, which is associated with BVP types 1 and 2. This publication describes and illustrates the macroscopic and histological appearance of BPV-associated papillomatous, fibropapillomatous or sarcoid-like lesions in Cape mountain zebra (Equus zebra zebra) from the Gariep Dam Nature Reserve, 2 giraffes (Giraffa camelopardalis) from the Kruger National Park, and a sable antelope (Hippotragus niger) from the Kimberley area of South Africa. An African buffalo (Syncerus caffer) cow from Kruger National Park also had papillomatous lesions but molecular characterisation of lesional virus was not done. Immunohistochemical staining using polyclonal rabbit antiserum to chemically disrupted BPV-1, which cross-reacts with the L1 capsid of most known papillomaviruses, was positive in cells of the stratum granulosum of lesions in Giraffe 1, the sable and the buffalo and negative in those of the zebra and Giraffe 2. Fibropapillomatous and sarcoid-like lesions from an adult bovine were used as positive control for the immunohistochemistry and are described and the immunohistochemistry illustrated for comparison. Macroscopically, both adult female giraffe had severely thickened multifocal to coalescing nodular and occasionally ulcerated lesions of the head, neck and trunk with local poorly-circumscribed invasion into the subcutis. Necropsy performed on the 2nd giraffe revealed neither internal metastases nor serious underlying disease. Giraffe 1 had scattered, and Giraffe 2 numerous, large, anaplastic, at times indistinctly multinucleated dermal fibroblasts with bizarre nuclei within the sarcoid-like lesions, which were BPV-1 positive in Giraffe 1 and BPV-1 and -2 positive in Giraffe 2 by RT-PCR. The sable antelope presented with a solitary large lesion just proximal to the right hind hoof, which recurred after excision, and was BPV-1 positive by RT-PCR. Other wart-like growths were present elsewhere on the body. The Cape mountain zebra either succumbed from their massive lesions or were euthanased or removed from the herd because of them. The lesions were BPV-1 and/or -2 positive by RT-PCR. The buffalo lesions were wart-like papillomatous projections in the inguinal and udder region. Stratum granulosum cells that stained immunohistochemically positive in the various species appeared koilocyte-like, as described in human papillomaviral lesions.     

Schiff-Sherrington syndrome in a 7-year-old zebra mare (Equus quagga)

A 7-year-old plains zebra (Equus quagga) mare was presented to the Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Germany as an emergency. The owner reported that the mare was unable to stand after a suspected traumatic episode at the home yard. The mare was transported in lateral recumbency in a trailer. Clinical examination revealed tachycardia (up to 102 beats/min), tachypnoea (28 breaths/min), mild fever (38.7°C) and clinical dehydration with elastic skin and dry and red mucous membranes. Neurological examination showed paraplegia with complete loss of nociception of the mid-thoracic region and caudal to it. In contrast, examination of the thoracic limbs revealed marked extensor rigidity and hyperaesthesia resulting in an enhanced acute response to minimal touch of the neck and shoulder region. Lateral radiographs of the thoracic vertebral column led to the diagnosis of a complete fracture of the vertebral body of the 7th thoracic (T) vertebra with suspected traumatic compression of the spinal cord. Post-mortem examination confirmed the diagnosis. Gross pathology revealed a complete comminuted fracture of T7 with marked compression of the spinal cord. This is the first report describing the clinical, radiological and pathological findings of a fracture of a thoracic vertebra leading to a Schiff-Sherrington syndrome in a zebra (Equus quagga).     

Klossiella equi infection in a Hartmann's Mountain zebra (Equus zebra hartmannae).

An 18-mo-old female Hartmann's Mountain zebra (Equus zebra hartmannae) died secondary to a traumatically induced cervical fracture. Microscopic examination of renal tissues revealed occasional coccidian sporocysts and budding sporonts containing sporoblasts encased within a bilaminated cell membrane within the renal tubules, compatible with a morphologic diagnosis of Klossiella equi, a coccidian parasite of renal parenchyma in equids. Repeated urinalyses of several Hartmann's Mountain zebra failed to reveal sporocysts, which are believed to be the infective stage of the parasite. The definitive life cycle of K. equi is unknown, although transmission is presumed to be via oral ingestion of sporocysts that are passed in the urine. Although generally considered an incidental finding, K. equi has been associated with nephrosis and nephritis in immune-compromised equids and should be considered when evaluating renal disease in equids, including zebras.     

Halicephalobus gingivalis (Nematoda) infection in a Grevy's zebra (Equus grevyi).

A 6-yr-old female Grevy's zebra (Equus grevyi) with a disseminated rhabditiform nematode infection is described. Antemortem clinical signs were limited to blindness and abnormal behavior believed to be caused by a recurrent nematode-induced uveitis. Histologic examination of the kidneys, heart, eyes, uterus, and lymph nodes revealed granulomas containing multiple sections of rhabditiform nematodes. Most of the recovered nematodes were larval stages with only a few adult females noted. The adults measured 243-297 microm x 11-16 microm (x = 269 x 14 microm). The distinctive rhabditiform esophagi had corpus:isthmus:bulb proportions of 19:11:5. On the basis of adult morphology, the nematode was identified as Halicephalobus gingivalis. This is the first report of this parasite in a zebra and indicates that this parasitic granulomatous disease should be considered in zebras with neurologic disease.     

Hydatidosis in a Chapman's zebra (Equus burchelli antiquorum).

A 14-year-old male Chapman's zebra had been treated for a cervical granulomatous cellulitis for 3 months prior to sudden death associated with myocardial fibrosis. Incidental findings at necropsy included multiple 3-8-cm unilocular cysts in the liver and lungs. Cysts contained either a clear fluid with or without hydatid sand or a gelatinous substance with foci of mineralization. Light and scanning electron microscopic examination of the hydatid sand revealed free protoscolices as well as intact and ruptured brood capsules with protoscolices attached to the germinal membrane. The protoscolices had 2 rows of 36-38 rostellar hooks with a length of 25-30 microm. The cyst wall consisted of inner germinal, intermediate laminated, and outer adventitial layers. Hydatidosis caused by Echinococcus granulosus was diagnosed based on the unilocular cysts, multiple protoscolices formed in a brood capsule, typical trilayered cyst wall, and herbivorous intermediate host. This is the first reported case of animal hydatidosis in Taiwan. The infection is thought to have been established 12 years ago in South Africa prior to importation.     

Studies on the parasites of zebras. IV. Cylicodontophorus reineckei n.sp. (Nematoda: Strongylidae) from the Burchell's zebra, Equus burchelli antiquorum H. Smith, 1841 and the mountain zebra, Equus zebra hartmannae Matschie, 1898

A new species of nematode, Cylicodontophorus reineckei, was collected from Burchell's zebra, Equus burchelli antiquorum H. Smith, 1841, in both the Etosha National and Kruger National Parks and from mountain zebra, Equus zebra hartmannae Matschie, 1898, in the Namib Naukluft Park in South West Africa/Namibia. These nematodes have an external leaf-crown with longer elements than those of the internal leaf-crown and a well-developed dorsal gutter. The very well-developed oesophageal funnel is both wider and deeper than the buccal capsule.     

Host social rank and parasites: plains zebra (Equus quagga) and intestinal helminths in Uganda

The main aim of this study was to evaluate the relationship between the social hierarchy of plain zebra, Equus quagga, and the level of parasitism. For the study 141 fecal samples from the same number of animals were collected within the two major populations of E. quagga of Uganda (Lake Mburo Conservation Area and Kidepo Valley National Park). Quantitative (eggs per gram of feces) and qualitative parasite assessment were performed with standard methods. The relationship between parasite burden and individual host features was analyzed using Generalized Linear Models. Strongyles, cestodes, Strongyloides sp. and oxiurids where present in the examined samples. Social rank and age class significantly affect all parasites' abundance with dominant individuals being less parasitized than subordinate individuals, regardless of the parasite groups excluding oxiurids. Sex could not been shown to be related with any of the found parasites. Age was positively related with strongyles and oxiurids abundance and negatively related with cestodes and Strongyloides sp. The main result of the present study was the evidence that social status influences parasite level with dominant zebras shedding less parasite eggs than subordinate ones. Social rank appears, therefore, as an important factor giving rise to parasite aggregation in plain zebras.     

Taxonomic status and distribution of the South African lizard Tetradactylus breyeri Roux (Gerrhosauridae)

The taxonomic status of the poorly known South African gerrhosaurid Tetradactylus breyeri, described by Roux in 1907 on the basis of a single specimen from the Transvaal, was investigated. The holotype and 14 other preserved specimens were examined and are described in detail. Prior to this study, only six specimens had been described in the literature. No evidence was found to warrant subspecific status for lizards from any part of the species’ range, despite the apparently isolated nature of populations, and T. breyeri is thus considered monotypic. The species occurs as three apparently isolated montane grassland to highveld grassland populations in the South African provinces of Mpumalanga, north-eastern Free State and KwaZulu-Natal. Despite recent surveys, very few specimens have been found, and the ‘rare’ status afforded the species in the South African Red Data Book should be retained.     

Detection of Sarcocystis neurona in the brain of a Grant's zebra (Equus burchelli bohmi).

An 8-yr-old intact male Grant's zebra (Equus burchelli bohmi) was referred to the Veterinary Medical Teaching Hospital of the University of California-Davis after being found in the owner's pasture obtunded and in lateral recumbency. The animal was hypothermic, weak, and unwilling to rise. There was no evidence of trauma, and the zebra had seemed normal the preceding evening. There was no extensor rigidity, and cranial nerve reflexes were normal. Flexor and extensor reflexes were weak upon initial examination. A complete blood count and serum biochemistry analysis revealed a mild leukocytosis, hyperfibrinogenemia, hypoglycemia, hyponatremia, hypochloremia, hypocalcemia, and hypoalbuminemia. Urinalysis was normal, and a urine toxicology screen for alkaloids was negative. No toxic substance was found in the hay or pasture grasses although the owner reported the presence of yellow star thistle and mushrooms in the pasture. The cerebrospinal fluid cytologic and biochemical analyses were normal, but antibodies to Sarcocystis neurona were detected. The zebra died despite aggressive supportive therapy over a 4-day period. The necropsy demonstrated severe gastrointestinal nematodiasis that could account for hypoalbuminemia and electrolyte abnormalities. Histopathologic examination of the nervous system revealed focal areas of perivascular cuffing in the brainstem that were comprised mainly of lymphocytes, monocytes, and plasma cells. Immunohistochemical staining identified the presence of S. neurona merozoites associated with the lesions. This zebra probably died from severe endoparasitism that resulted in malabsorption, weakness, and recumbency rather than from encephalitis associated with S. neurona merozoites. Equine protozoal myeloencephalitis has not been reported previously in nondomestic equids.     

Prevalence of Helminth Infections in the Cape Hare (Lepus capensis) in Iran

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