Objective—To evaluate the diagnostic value of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations in Doberman Pinschers in various stages of dilated cardiomyopathy (DCM). Animals—328 Doberman Pinschers. Procedures—Staging of DCM was determined via analysis of results of physical examinations, 24-hour ambulatory ECG (Holter) recordings, and echocardiographic evaluations. Plasma samples for NT-proBNP assays were obtained at each examination. Concentrations of NT-proBNP were measured in 337 samples obtained from 196 healthy Doberman Pinschers (control dogs) and in 195 samples obtained from 132 Doberman Pinschers in various stages of DCM. These included dogs that had ventricular premature contractions (VPCs; 79 samples), echocardiographic changes (23 samples), or both (51 samples); 16 samples were from dogs with overt DCM, and 26 were from dogs that were considered normal during initial examination but developed DCM within 1.5 years after this assessment. Receiver operating characteristic curves were analyzed to determine sensitivity and specificity of NT-proBNP concentrations for detection of DCM. Results—NT-proBNP concentrations in dogs that had or developed DCM were significantly higher than those of control dogs. Sensitivity and specificity of NT-proBNP concentrations (cutoff value, > 400 pmol/L) to detect all stages of DCM were 81.1 % and 75.0%, respectively; sensitivity was 90.0% and specificity was 75.0% to predict echocardiographic changes. Specificity to detect echocardiographic changes was 90.4% at a cutoff value of 550 pmol/L. Conclusions and Clinical Relevance—Plasma concentrations of NT-proBNP were increased in dogs with DCM and in apparently healthy dogs that developed DCM within 1.5 years after samples were obtained, compared with concentrations in control dogs.

Objective—To evaluate symmetry of the hind limbs in orthopedically normal trotting dogs. Animals—19 orthopedically normal Labrador Retrievers with no history of lameness. Procedures—Retroreflective markers were applied to the hind limb joints, and a 4-camera kinematic system captured positional data at 200 Hz in tandem with force platform data collection while the dogs trotted. Morphometric data were combined with kinematic and force data in an inverse dynamics method to calculate net joint moments and powers at the joints as well as total support moment for each limb. Dogs were identified as right or left dominant when their total support moment was > 10% asymmetric between sides. Results—10 of the 19 dogs were mechanically dominant in the right hind limb as determined by their total support moments. One dog was left dominant, and the remaining 8 were symmetric. Right-dominant dogs had larger net joint moments at the right hip, tarsal, and metatarsophalangeal joints and a smaller moment at the right stifle joint, compared with values for the left hind limb. The 1 left-dominant dog had the exact opposite findings. Hip and stifle joint moments and powers varied between limbs of the right-dominant and left-dominant groups in the timing of their transition from negative to positive, and power amplitudes varied at the hip, tarsal, and metatarsophalangeal joints but not the stifle joint. Conclusions and Clinical Relevance—Sound trotting dogs can have asymmetries in limb and joint mechanics. These natural mechanical asymmetries should be taken into account when considering models to evaluate stresses at joints and when considering surgery for cruciate ligament rupture.

Objective: To compare temporospatial variables (TSVs) and kinetic variables (KVs) for fore-limbs and hind limbs of small and large dogs of various breeds during walking and to determine associations among body weight (BW), TSVs, and KVs in these groups. Animals: 12 adult dogs with no evidence of lameness. Procedures: Dogs (grouped according to BW as small [< 10 kg; n = 6] or large [> 25 kg; 6]) were walked in a straight line at their preferred velocity on a wooden platform with an embedded pressure-sensing walkway. Five valid trials were analyzed for each dog; mean TSVs and KVs were determined for each group. The TSVs and KVs for forelimbs and hind limbs were compared between groups, and correlations among BW, TSVs, and KVs were determined. Results: Small dogs had significantly smaller TSVs and KVs than did large dogs. Temporal variables of small dogs and absolute vertical force variables of small and large dogs increased as BW increased. However, normalized peak vertical force and weight distribution values among the 4 limbs were similar between groups. Conclusions and Clinical Relevance: Substantial similarities and differences were detected in gait characteristics between small and large dogs. Results indicated TSVs and KVs can be used for comparison of the walking gait between dogs or for comparison of variables between limbs in an individual dog. Use of the pressure-sensing walkway is a simple method for acquisition of TSVs and KVs for large and small dogs.

The study aimed to assess the long-term population dynamics of questing Rhipicephalus appendiculatus and Rhipicephalus zambeziensis in two landscape zones of the Kruger National Park (KNP). Ticks were collected by dragging the vegetation monthly in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road and Skukuza) from August 1988 to March 2002. Larvae were the most commonly collected stage of both species. More R. appendiculatus were collected at Nhlowa Road than at Skukuza, with larvae being most abundant from May to August, while nymphs were most abundant from August to December. Larvae were most commonly collected in the gullies from 1991 to 1994, but in the grassland and woodland habitats from 1998 onwards. Nymphs were most commonly collected in the grassland and woodland. More R. zambeziensis were collected at Skukuza than at Nhlowa Road, with larvae being most abundant from May to September, while nymphs were most abundant from August to November. Larvae and nymphs were most commonly collected in the woodland and gullies and least commonly in the grassland (p < 0.01). The lowest numbers of R. appendiculatus were collected in the mid-1990s after the 1991/1992 drought. Rhipicephalus zambeziensis numbers declined after 1991 and even further after 1998, dropping to their lowest levels during 2002. The changes in numbers of these two species reflected changes in rainfall and the populations of several of their large herbivore hosts, as well as differences in the relative humidity between the two sites over time

Despite many studies regarding tick ecology, limited information on long-term changes in tick populations exist. This study assessed the long-term population dynamics of the less frequently collected questing ixodid ticks in the Kruger National Park (KNP). From 1988 to 2002, monthly dragging of the vegetation was performed in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road, Landscape Zone 17, and Skukuza, Landscape Zone 4). Amblyomma marmoreum and Rhipicephalus evertsi evertsi were collected as larvae most commonly. Most A. marmoreum larvae were collected at Skukuza and numbers peaked from March to July. More R. evertsi evertsi larvae were collected at Nhlowa Road and numbers peaked in summer and in winter, while at Skukuza there was a single peak in spring. Haemaphysalis elliptica, Rhipicephalus simus and Rhipicephalus turanicus were collected as adults most commonly. More Ha. elliptica and R. turanicus were collected at Nhlowa Road than at Skukuza, while R. simus numbers from the two sites were approximately equal. Ha. elliptica were collected most often between February and June, and R. simus and R. turanicus during February and March. All three species were collected more frequently in gullies than in grassland or woodland. Their numbers increased in 1994/1995 following an eruption of rodents, the preferred hosts of the immature stages. The different host-seeking strategies of ticks largely determine the development stage at which they are likely to be collected during vegetation dragging and reflect a complex interaction between ticks, their hosts and the environment

Several studies on ticks infesting small mammals, including elephant shrews, have been conducted in South Africa; however, these studies have included only a single four-toed elephant shrew and no hedgehogs. This study thus aimed to identify and quantify the ixodid ticks infesting four-toed elephant shrews and Southern African hedgehogs. Four-toed elephant shrews (Petrodromus tetradactylus) were trapped in dense shrub undergrowth in a nature reserve in north-eastern KwaZulu-Natal. They were separately housed, first in cages and later in glass terraria fitted with wire-mesh bases to allow detached ticks to fall through for collection. Southern African hedgehogs (Atelerix frontalis) were hand caught on a farm in the eastern region of the Northern Cape Province and all visible ticks were collected by means of tweezers while the animals were anaesthetised. The ticks from each animal were preserved separately in 70% ethanol for later identification and counting. The immature stages of five ixodid tick species were collected from the elephant shrews, of which Rhipicephalus muehlensi was the most common. It has not been recorded previously on any species of elephant shrew. Three ixodid tick species were collected from the hedgehogs. Large numbers of adult Haemaphysalis colesbergensis, which has not been encountered previously on hedgehogs, were collected from these animals. Four-toed elephant shrews are good hosts of the larvae and nymphs of R. muehlensi, and Southern African hedgehogs are good hosts of adult H. colesbergensis

Protozoa species were identified in rumen contents of four domestic sheep (Ovis aries) from South Africa. All animals were fed a forage diet which consisted of 50% lucerne and 50% teff hay. Ten new host records were identified, bringing the total number of species and forms observed in sheep in South Africa to 30. The occurrence and geographic distribution of ciliate protozoa in both domestic and wild sheep from around the world are summarised. It was found that 15 genera and 131 species occur in domestic sheep globally.

Bovine viral diarrhoea virus (BVDV) infection is an important viral infection affecting the cattle industry today. The prevalence of this infection in South African feedlots is unknown. Ear notch biopsies were collected from chronic poor doers and animals that appeared unthrifty upon entering feedlots, as well as animals entering the hospital pen with respiratory disease for the first time. A total of 1690 samples were collected: 1074 from the former category and 616 from the latter. A routine immunohistochemistry staining protocol showed that 49 animals tested positive, of which 43 (4%) came from the feedlot entry group and six (1%) from the hospitalised group. The prevalence of persistently infected cattle from this selected, nonrandom sample entering six large South African feedlots was found to be 2.9%, which is higher than the international rule of thumb that 0.5% of all cattle entering feedlots are persistently infected. There was no clear correlation between persistent infection and respiratory disease. Serum samples were also collected when possible and 10 positive cases were found. Results from enzyme-linked immunosorbent assays for antigen and antibody performed on these sera correlated well with those from the immunohistochemistry staining method in six cases, but in four cases the animals tested falsely positive owing to nonspecific staining. Immunohistochemistry staining on ear notch biopsies is thus a reliable diagnostic method to identify persistently infected animals with BVDV, but the pathologist should be aware of nonspecific positive staining.

Ticks, as vectors of disease and damage agents, impact directly and indirectly on the economy of the livestock industry in southern Africa. This study surveyed the occurrence and distribution of ticks infesting livestock across the North West province, South Africa. During three phases in consecutive years, officers of the provincial Veterinary Department collected specimens monthly from livestock hosts at specified sites across the province. Data analysis constituted the fourth phase of the study. A total of 1090 collections from 265 sites yielded 42 566 tick specimens, comprising 22 different tick species (18 ixodids, 4 argasids). The specimens represent all of the major tick vectors of disease that occur in South Africa. The major tick-borne diseases (i.e. heartwater, both African and Asiatic bovine babesiosis and anaplasmosis) were found to be prevalent mainly in the north-eastern region of the province, which also displayed the highest tick species diversity. The central region appears transitory to some of the major vectors. Although some tick species were contained within specific regions, others were widespread across the province. Associated serology data show that most herds sampled in areas endemic for babesiosis and anaplasmosis in the north-eastern region are endemically unstable and at risk to these tick-borne diseases should vector control measures become ineffective.

Many studies on the population dynamics of questing ticks on pastures and of parasitic ticks on cattle have been conducted. Few, however, have attempted to link the two in a single study. This study aimed to assess the population dynamics of questing ixodid ticks on pastures and of adult ticks on two breeds of cattle with different levels of susceptibility to tick infestation on the same pastures. Between January 2005 and December 2009 questing ixodid ticks were collected monthly from natural pastures at the Döhne Agricultural Development Institute and at the adjacent Campagna Production System in the Amahlathi District, Eastern Cape province, South Africa. Between February 2007 and January 2010 adult ticks were collected monthly from Bonsmara and Nguni cattle grazing these pastures. Ten tick species were collected from the pastures and 12 from the cattle. Significantly more questing larvae of Rhipicephalus appendiculatus, Rhipicephalus decoloratus, Rhipicephalus evertsi evertsi and Rhipicephalus microplus were recovered from the pastures grazed by Bonsmara cattle than from those grazed by Nguni cattle (p <0.05). Significantly more adult Hyalomma rufipes, Rhipicephalus follis, R. appendiculatus, R. decoloratus, R. evertsi evertsi and R. microplus were collected from the Bonsmara cattle than from the Nguni cattle (p < 0.05). The study showed that Nguni cattle are less susceptible to tick infestation than are Bonsmara cattle and fewer questing ticks are collected from pastures grazed by Nguni cattle than by Bonsmara cattle.