Serial changes in the concentrations of cortisol and thyroid hormones in Beagle dogs infected with Babesia rossi.

An experimental infection using Babesia (B.) rossi was performed in healthy male Beagle dogs to assess the changes in endocrine variables during disease. Two dogs were infected with a low dose (LD) of parasite inoculum (104 parasites) and three dogs were infected with a high dose (HD) (108 parasites). Basal serum cortisol, thyroxine (T4), and thyrotropin (TSH) concentrations were measured every second day. Samples were analyzed using a solid- phase, competitive chemiluminescent enzyme immunoassay (Immulyte® 2000, Siemens). Variables were compared between groups and timepoints using linear mixed models. In both groups, the median cortisol concentration increased, whilst the median T4 concentration decreased after infection, with a return towards baseline concentration post treatment. The highest cortisol and the lowest T4 concentrations were reached at 96 h and 108 h post infection, respectively, in the HD group and slightly later at 108 and 144 h post-infection, respectively, in the LD group. A higher cortisol concentration with a more rapid increase, and a lower T4 concentration with a more rapid decline, were associated with disease severity and a higher dose of parasite inoculum. The TSH concentration remained within the reference interval throughout the study period. This study illustrated the temporal changes in endocrine parameters during experimental B. rossi infection and demonstrated that cortisol and T4 tracked the severity of disease, albeit in opposite directions.

Oral bait preferences for rabies vaccination in free-ranging black-backed jackal (Canis mesomelas) and non-target species in a multi-site field study in a peri-urban protected area in South Africa.

Black-backed jackals (Canis mesomelas) are small meso-predators that occur in the wild and around cities and towns in southern Africa and have been associated with the spread of rabies in South Africa. Oral bait rabies vaccine has been used in Europe and the USA for the control of rabies in reservoir species. The effectiveness of an oral vaccination strategy depends not only on the efficacy of the vaccine but on the uptake of the bait in the target species. This study evaluated factors associated with the uptake of oral bait by free ranging jackal and other wildlife species in a multi-site field study in Gauteng Province, South Africa. Three different baits were offered: commercial fishmeal polymer, pieces of red meat and chicken heads. Bait uptake was observed using camera traps and patterns of uptake assessed by multiple correspondence analysis and Cox proportional hazards models. In general, all the baits were well accepted with an uptake of 91%. Median consumption time of bait for jackal was 18 h (IQR: 8-21 hours; range 7-66 hours) and for all other species it was 21 h (IQR: 4-44, range 1-283). In species other than jackals there was a faster uptake in the winter months when less food was available, and the vegetation was sparse, whereas jackal showed no seasonal preference. Jackal consumed 20% of baits placed and took all three bait types but showed a clear preference for chicken heads if available (Hazard ratio (HR) = 3.41; 95%CI: 1.16-9.99; p = 0.025). Species other than carnivores preferred fishmeal polymer or red meat. Jackals showed no preference for time of day whereas herbivores and other species clearly preferred day; other carnivores preferred either day or night but not both, depending upon species. This study showed that chicken heads may be the preferred bait type for oral vaccination of black-backed jackal in this area, and that consideration should be given to placing bait during summer and at dusk, in order to minimize uptake by non-target species.

Oocyte quality and viability in Nguni and Hereford cows exposed to different levels of dietary protein.

High blood urea nitrogen (BUN) concentration decreases fertility in ruminants. Nguni cattle are reported to maintain BUN concentration more efficiently than other beef breeds. Our objectives were to determine if BUN concentration differed between Nguni and Hereford cows exposed to a high protein ration, and if breed or BUN and serum protein concentrations at the time of oocyte pick-up affected oocyte quantity, quality, and viability. Twelve Nguni and 10 Hereford cows were randomized into high or normal BUN-inducing diets in a crossover design. Ultrasound-guided oocyte pick-up was performed twice weekly; oocytes were counted, visually graded and the viable oocytes were pooled by treatment and breed for in vitro maturation, fertilization, and culture. Nguni cows on the highest protein ration achieved lower mean BUN concentration than Herefords (P < 0.05), and Nguni cows reached BUN concentrations above 20 mg/dL less frequently than Herefords (P = 0.03). Donor BUN concentration above 20 mg/dL at the time of oocyte pick-up, but not breed, independently decreased the number of good quality oocytes harvested. Increasing weighted mean serum albumin of donor cows was independently associated with the number of oocytes that cleaved by day 2 and that reached morula stage by day 7 (P = 0.01). In conclusion, Nguni cows reached the critical threshold of 20 mg/dL BUN less frequently than Herefords; BUN of donor cows above 20 mg/dL negatively affected visual oocyte quality independent of breed, and increasing serum albumin of donor cows improved viability of bovine oocytes.

Evaluation of positive Rift Valley fever virus formalin-fixed paraffin embedded samples as a source of sequence data for retrospective phylogenetic analysis.

Rift Valley fever (RVF), caused by an arthropod borne Phlebovirus in the family Bunyaviridae, is a haemorrhagic disease that affects ruminants and humans. Due to the zoonotic nature of the virus, a biosafety level 3 laboratory is required for isolation of the virus. Fresh and frozen samples are the preferred sample type for isolation and acquisition of sequence data. However, these samples are scarce in addition to posing a health risk to laboratory personnel. Archived formalin-fixed, paraffin-embedded (FFPE) tissue samples are safe and readily available, however FFPE derived RNA is in most cases degraded and cross-linked in peptide bonds and it is unknown whether the sample type would be suitable as reference material for retrospective phylogenetic studies. A RT-PCR assay targeting a 490 nt portion of the structural GN glycoprotein encoding gene of the RVFV M-segment was applied to total RNA extracted from archived RVFV positive FFPE samples. Several attempts to obtain target amplicons were unsuccessful. FFPE samples were then analysed using next generation sequencing (NGS), i.e. Truseq® (Illumina) and sequenced on the Miseq® genome analyser (Illumina). Using reference mapping, gapped virus sequence data of varying degrees of shallow depth was aligned to a reference sequence. However, the NGS did not yield long enough contigs that consistently covered the same genome regions in all samples to allow phylogenetic analysis.

Characteristics of Foot-and-Mouth Disease Viral Strains Circulating at the Wildlife/livestock Interface of the Great Limpopo Transfrontier Conservation Area.

Foot-and-mouth disease (FMD) inflicts severe economic losses within infected countries and is arguably the most important trade-restricting livestock disease in the world. In southern Africa, infected African buffaloes (Syncerus caffer) are the major reservoir of the South African Territories (SAT) types of the virus. With the progressive expansion of transfrontier conservation areas (TFCAs), the risk of FMD outbreaks is expected to increase due to a higher probability of buffalo/livestock contacts. To investigate the dynamics of FMD within and around the Great Limpopo TFCA (GLTFCA), 5 herds of buffaloes were sampled in June 2010 to characterize circulating viruses in South Africa and Zimbabwe. Three SAT-2 and three SAT-3 viral strains were isolated in both countries, including one that was genetically linked with a recent SAT-2 outbreak in Mozambique in 2011. In addition, two groups of unvaccinated cattle (n = 192) were serologically monitored for 1 year at the wildlife/livestock interface of Gonarezhou National Park (GNP) in Zimbabwe between April 2009 and January 2010, using the liquid-phase blocking ELISA (LPBE) and a test for antibodies directed against non-structural proteins (NSP). Neither clinical signs nor vaccination of cattle were reported during the study, yet a high proportion of the monitored cattle showed antibody responses against SAT-3 and SAT-1. Antibodies against NSP were also detected in 10% of the monitored cattle. The results of this study suggest that cattle grazing in areas adjacent to the GLTFCA can be infected by buffalo or other infected livestock and that cattle trade movements can act as efficient disseminators of FMD viruses to areas several hundred kilometres from the virus source. Current methods of surveillance of FMD at the GLTFCA interface seem insufficient to control for FMD emergence and dissemination and require urgent reassessment and regional coordination.

Epidemiological surveillance methods for vector-borne diseases.

Compared with many other diseases, the ever-increasing threat of vector-borne diseases (VBDs) represents a great challenge to public and animal health managers. Complex life cycles, changing distribution ranges, a variety of potential vectors and hosts, and the possible role of reservoirs make surveillance for VBDs a grave concern in a changing environment with increasing economic constraints. Surveillance activities may have various specific objectives and may focus on clinical disease, pathogens, vectors, hosts and/or reservoirs, but ultimately such activities should improve our ability to predict, prevent and/or control the diseases concerned. This paper briefly reviews existing and newly developed tools for the surveillance of VBDs. A range of examples, by no means exhaustive, illustrates that VBD surveillance usually involves a combination of methods to achieve its aims, and is best accomplished when these techniques are adapted to the specific environment and constraints of the region. More so than any other diseases, VBDs respect no administrative boundaries; in addition, animal, human and commodity movements are increasing dramatically, with illegal or unknown movements difficult to quantify. Vector-borne disease surveillance therefore becomes a serious issue for local and national organisations and is being conducted more and more at the regional and international level through multidisciplinary networks. With economic and logistical constraints, tools for optimising and evaluating the performance of surveillance systems are essential and examples of recent developments in this area are included. The continuous development of mapping, analytical and modelling tools provides us with an enhanced ability to interpret, visualise and communicate surveillance results. This review also demonstrates the importance of the link between surveillance and research, with interactions and benefits in both directions.

Evaluation of enzyme-linked immunosorbent assays and a haemagglutination inhibition tests for the detection of antibodies to Newcastle disease virus in village chickens using a Bayesian approach.

Newcastle disease (ND) is an endemic disease in village chickens in Ethiopia with substantial economic importance. The sensitivity (Se) and specificity (Sp) of a blocking enzyme-linked immunosorbent assay (bELISA, Svanova Biotech), indirect ELISA (iELISA, Laboratoire Service International) and haemagglutination inhibition (HI) test for ND virus (NDV) antibody detection were evaluated in a Bayesian framework in the absence of a gold standard test, on sera collected from unvaccinated chickens kept under the village production system in household flocks and at markets in two woredas (i.e. districts) of the Eastern Shewa zone, Ethiopia. The outcomes of the iELISA test differed dramatically from those of the two other tests with 92% of the samples testing positive as compared with less than 15% for bELISA and HI. iELISA results were also inconsistent with previous estimations of Newcastle serological prevalence. The information provided by the iELISA test was thus considered as highly unreliable, probably due to an extremely low specificity, and thus not considered in the Bayesian models aiming at estimating serological prevalence and test performance parameters. Bayesian modelling of HI and bELISA test results suggested that bELISA had both the highest Se (86.6%; 95% posterior credible interval (PCI): 61.8%; 98.5%), and the highest Sp (98.3%; 95% PCI: 97.2%; 99.5%), while HI had a Se of 80.2% (95% PCI: 59.1%; 94.3%), and a Sp of 96.1% (95% PCI: 95.1%; 97.4%). Model selection and the range of the posterior distribution of the correlation between bELISA and HI test outcomes for truly seropositive animals (median at 0.461; PCI: -0.055; 0.894) suggested a tendency for bELISA and HI to detect the same truly positive animals and to fail to detect the same truly positive animals. The use of bELISA in screening and surveillance for NDV antibodies is indicated given its high Se and Sp, in addition to its ease of automation to handle large numbers of samples compared to HI. The latter can be used as confirmatory test where an ELISA test with moderate or low specificity is used although the likely positive dependence with bELISA implies that HI and bELISA provide similar information on truly positive animals. Evaluation of commercial ELISAs is indicated before their wider use in village chicken populations to avoid erroneous inferences.

Evaluation of pre-breeding reproductive tract scoring as a predictor of long term reproductive performance in beef heifers.

In a 7-year longitudinal study 292 Bovelder beef cows in a restricted breeding system in South Africa were observed from 1 to 2 days before their first breeding season, when reproductive tract scoring (RTS, scored from 1 to 5) was performed, until weaning their 5th calves. The objective was to determine whether pre-breeding RTS in heifers is a valid tool to predict long-term reproductive performance. Outcomes measured were failure to show oestrus during the first 24 days of the first 50-day AI season (24-day anoestrus), failure to become pregnant during each yearly artificial insemination (AI) season (reproductive failure), number of days from the start of each AI season to calving, and number of years to reproductive failure. The effect of RTS on each outcome was adjusted for year of birth, pre-breeding age, BW and body condition score (BCS), and for 24-day anoestrus, bull, gestation length, previous days to calving and previous cow efficiency index, the latter two in the case of the 2nd to the 5th calving season. During their first breeding season, heifers with RTS 1 and 2 combined were more likely to be in anoestrus for the first 24 days (OR=3.0, 95% CI 1.5, 6.4, P=0.003), and were also more likely to fail to become pregnant even after adjusting for 24-day anoestrus (OR=2.1, 95% CI 1.1, 3.9, P=0.025), compared to those with RTS 4 and 5 combined. Animals with RTS 1 and 2 combined were at increased risk of early reproductive failure compared to those with RTS 4 and 5 combined (HR=1.4, 95% CI 1.0, 1.9, P=0.045) although RTS was not associated with calving rate or days to calving after the second calving season. Low RTS at a threshold of 1 had consistent specificity of ≥94% for both 24-day anoestrus and pregnancy failure, however its predictive value was lower in the age cohort with a higher prevalence of anoestrus. We conclude that RTS is a valid management tool for culling decisions intended to improve long-term reproductive success in a seasonal breeding system, by excluding heifers that are likely to fail to become pregnant or likely to calve late during their first calving season.

A new application of pelvis area data as culling tool to aid in the management of dystocia in heifers.

Although fetomaternal disproportion is the major cause of dystocia in heifers, pelvis area (PA) is not recommended as a culling tool due to its relatively low importance and genetic correlation with calf birth weight (BWT), the most important factor associated with dystocia. The objective of this observational study of 484 limited bred yearling beef heifers was to compare the effects of different methods of adjustment of PA data for culling to select against dystocia. Multivariable analyses were used to determine predictors of PA, calf BWT, and dystocia. Hypothetical culling rates of 10 and 20% were then applied after ranking heifers by each of the following: unadjusted PA, PA adjusted to 365 d of age by subtracting 0.27 cm(2) per day of age difference between each heifer's age and 365 d (APA), PA:prebreeding BW ratio (PA:BW), PA adjusted to the median BW of the group using the regression coefficient of PA on BW within age group (BWPA), and PA similarly adjusted to the median lean BW (LBWPA). Dam parity, sire, prebreeding age, prebreeding BW, and prebreeding BCS were associated with PA whereas dam parity, sire, own BWT, PA, AI bull, and calf gender were associated with calf BWT (P < 0.05). Dam parity, calf BWT, and either BWPA or LBWPA were the only independent predictors of dystocia (P < 0.05). Adjusting PA to BW or lean BW (LBW) improved the sensitivity and specificity to predict dystocia. After hypothetical culling by PA, retained heifers were heavier and had a higher calving rate and calves tended to be heavier at birth compared to culled heifers, but dystocia rates were not different. Culling by APA resulted in similar effects, except that dystocia rate tended to be lower in retained heifers. Culling by PA:BW resulted in lower dystocia rate in retained than in culled heifers, but retained heifers had lower prebreeding BW than culls. Culling by BWPA and LBWPA resulted in lower proportions with dystocia and a tendency towards higher calving rates in the retained heifers, without affecting the prebreeding BW or calf BWT. It is concluded that pelvimetry is a useful culling tool to aid in the management of dystocia in yearling heifers and that adjustment of PA to median BW or LBW within age group improves its accuracy and avoids the undesirable side effects.

The carrier prevalence of severe combined immunodeficiency, lavender foal syndrome and cerebellar abiotrophy in Arabian horses in South Africa.

REASONS FOR PERFORMING STUDY: The carrier prevalence of severe combined immunodeficiency (SCID), lavender foal syndrome (LFS) and cerebellar abiotrophy (CA) in Arabian foals in South Africa was determined in order to quantify the potential impact of these conditions locally. Furthermore, the carrier prevalence of SCID prior to and following the introduction of a genetic test was compared to evaluate the effect of testing in the population. OBJECTIVES: To estimate the carrier prevalence of SCID, LFS and CA in registered purebred Arabians born in South Africa in the 2004/5 and 2009/10 foaling seasons and compare the changes in prevalence in these disorders between the 2 groups of foals. STUDY DESIGN: Cross-sectional survey. METHODS: Samples were collected from individuals randomly selected from 2 populations of purebred Arabian foals born during the 2004/5 and 2009/10 foaling seasons. Genetic testing for SCID, LFS and CA was performed on DNA extracts using specific polymerase chain reactions, with the products being analysed using fragment analysis on a genetic analyser. RESULTS: The carrier prevalence of LFS and CA for the 2009/10 season was 11.7% (95% confidence interval [CI] 7.6-17.0%) and 5.1% (95% CI 2.5-9.1%), respectively, with no statistically significant change in prevalence between the 2004/5 and 2009/10 foaling seasons. However, the carrier prevalence of SCID was found to have decreased significantly from 6.4% (95% CI 4.8-8.3%) in the 2004/5 foals to 3.4% (95% CI 2.2-5.1%) in the 2009/10 foals (P = 0.009). CONCLUSIONS: The results of this study indicate that genetic screening of Arabian horses for SCID may have played a role in significantly reducing the carrier prevalence within the breeding population and thereby reducing the birth of clinically affected individuals. This study provides an indication of the positive effect of genetic screening for specific conditions in horses.

Herd-level risk factors for Campylobacter fetus infection, Brucella seropositivity and within-herd seroprevalence of brucellosis in cattle in northern Nigeria.

Brucellosis and campylobacteriosis are economically important diseases affecting bovine reproductive efficiency in Nigeria. A questionnaire-based survey was conducted in 271 cattle herds in Adamawa, Kaduna and Kano states of northern Nigeria using multistage cluster sampling. Serum from 4745 mature animals was tested for Brucella antibodies using the Rose-Bengal plate test and positives were confirmed in series-testing protocol using competitive enzyme-linked immunosorbent assay. Preputial scrapings from 602 bulls were tested using culture and identification for Campylobacter fetus. For each disease, a herd was classified as positive if one or more animals tested positive. For each herd, information on potential managemental and environmental risk factors was collected through a questionnaire administered during an interview with the manager, owner or herdsman. Multiple logistic regression models were used to model the odds of herd infection for each disease. A zero-inflated Poisson model was used to model the count of Brucella-positive animals within herds, with the number tested as an exposure variable. The presence of small ruminants (sheep and/or goats) on the same farm, and buying-in of >3 new animals in the previous year or failure to practice quarantine were associated with increased odds of herd-level campylobacteriosis and brucellosis, as well as increased within-herd counts of Brucella-positive animals. In addition, high rainfall, initial acquisition of animals from markets, practice of gynaecological examination and failure to practice herd prophylactic measures were positively associated with the odds of C. fetus infection in the herd. Herd size of >15, pastoral management system and presence of handling facility on the farm were associated with increased odds, and gynaecological examination with reduced odds of herd-level Brucella seropositivity. Furthermore, the zero-inflated Poisson model showed that borrowing or sharing of bulls was associated with higher counts, and provision of mineral supplement with lower counts of Brucella-positive cattle within herds. Identification of risk factors for bovine campylobacteriosis and brucellosis can help to identify appropriate control measures, and the use of zero-inflated count model can provide more specific information on these risk factors.

Genetic characterization of Cryptosporidium spp. in diarrhoeic children from four provinces in South Africa.

The diversity of Cryptosporidium at species, subtype family and subtype level in diarrhoeic children was investigated in four provinces in South Africa. A total of 442 stool samples from children <5 years of age were collected under a large rotavirus surveillance programme and analysed by Ziehl-Neelsen acid-fast staining. Fifty-four (12.2%) were positive for Cryptosporidium, of which 25 were genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and DNA sequence analyses of the 18S rRNA gene. The majority of genotyped specimens were identified as C. hominis (76%), and a high genetic diversity was found with five different C. hominis subtype families (Ia, Ib, Id, Ie and If). Cryptosporidium parvum was found in 20% of the isolates, and three subtype families were identified (IIc, IIe and IIb), with subtype family IIc being the most common. One specimen was identified as C. meleagridis of the subtype family IIId. These results are in accordance with findings from other developing countries and report for the first time the presence in South Africa of C. meleagridis, various subtypes of C. parvum and the subtype family Ie of C. hominis. The results suggest that C. hominis and anthroponotic C. parvum subtypes are the major cause of cryptosporidiosis in South Africa. Further molecular studies are needed to better understand the epidemiology and public health importance of Cryptosporidium in humans in South Africa.

Hemostatic abnormalities in uncomplicated babesiosis (Babesia rossi) in dogs.

BACKGROUND: Babesiosis in dogs is associated with severe thrombocytopenia; yet infected dogs rarely show clinical signs of hemorrhage. HYPOTHESIS: Dogs with uncomplicated babesiosis have normal hemostatic capacity despite severe thrombocytopenia. ANIMALS: Nineteen client-owned dogs with uncomplicated babesiosis; 10 healthy controls. METHODS: A prospective, cross-sectional, observational study. Thromboelastography (TEG), prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimers, and antithrombin (AT) measured in both groups. Statistical significance set at P < .01. RESULTS: Babesiosis group hematocrit and platelet count significantly lower than controls (0.29 versus 0.50 L/L; P < .001 and 20.0 versus 374.5 × 10(9)/L; P < .001, respectively). Except for K, no significant difference in TEG variables between groups. Hemostatic variables for babesiosis group versus controls (mean ± SD); R: 5.9 ± 1.8 versus 4.6 ± 0.9 min (P = .048); K: 2.8 ± 1.1 versus 1.9 ± 0.6 min (P = .003); angle: 55.5 ± 11.7 versus 62.2 ± 4.1 degrees (P = .036); MA: 48.4 ± 9.7 versus 57.2 ± 5.2 mm (P = 0.013); G: 5.1 ± 1.9 versus 6.9 ± 1.5 dyn/cm(2) (P = .019); LY30 (median, range): 0 (0-5.7) versus 0.6% (0-6.1) (P = .152); and LY60: 0 (0-8.8) versus 3.1% (0-13.1) (P = .012). AT activity significantly lower (105.2 ± 16.5 versus 127.8 ± 15.4%; P = .001). Fibrinogen concentration significantly higher in babesiosis group (5.7 ± 1.3 versus. 3.0 ± 0.7 g/L; P < .001). CONCLUSION AND CLINICAL IMPORTANCE: Despite severe thrombocytopenia, dogs with uncomplicated babesiosis did not have clinical signs of hemorrhage and TEG variables were normal, which could indicate a normocoagulable state.

Risk factors for farm-level African swine fever infection in major pig-producing areas in Nigeria, 1997-2011.

African swine fever (ASF) is an economically devastating disease for the pig industry, especially in Africa. Identifying what supports infection on pig farms in this region remains the key component in developing a risk-based approach to understanding the epidemiology of ASF and controlling the disease. Nigeria was used for this matched case-control study, because there is perpetual infection in some areas, while contiguous areas are intermittently infected. Risk factors and biosecurity practices in pig farms were evaluated in association with ASF infection. Subsets of farms located in high-density pig population areas and high-risk areas for ASF infection were randomly selected for analysis. Most plausible risk factor variables from the univariable analysis included in the multivariable analysis include: owner of farm had regular contact with infected farms and other farmers, untested pigs were routinely purchased into the farm in the course of outbreaks, there was an infected neighbourhood, other livestock were kept alongside pigs, there was a presence of an abattoir/slaughter slab in pig communities, wild birds had free access to pig pens, tools and implements were routinely shared by pig farmers, there was free access to feed stores by rats, and feed was purchased from a commercial source. Only the presence of an abattoir in a pig farming community (OR=8.20; CI(95%)=2.73, 24.63; P<0.001) and the presence of an infected pig farm in the neighbourhood (OR=3.26; CI(95%)=1.20, 8.83; P=0.02) were significant. There was a marginally significant negative association (protective) between risk of ASF infection and sharing farm tools and equipment (OR=0.35; CI(95%)=0.12, 1.01; P=0.05). Of the 28 biosecurity measures evaluated, food and water control (OR=0.14; CI(95%)=0.04, 0.46; P<0.001), separation/isolation of sick pigs (OR=0.14; CI(95%)=0.04, 0.53; P=0.004) and washing and disinfection of farm equipment and tools (OR=0.27; CI(95%)=0.10, 0.78; P=0.02) were negatively associated (protective) with ASF infection. Consultation and visits by veterinarian/paraveterinarians when animals were sick (OR=8.11; CI(95%)=2.13, 30.90; P=0.002), and pest and rodent control were positively associated with ASF infection of Nigerian farms (OR=4.94; CI(95%)=1.84, 13.29; P=0.002). The presentation of sick and unthrifty pigs for slaughter at abattoirs, farmers' inadvertent role, an infected neighbourhood, a pig to pig contact, rodents and wild birds may contribute to infections of farms, whereas washing, disinfection of tools, food and water control, and separation of sick pigs reduces the likelihood of infections. Underlying reasons for these observations and strategies for control are discussed.

Seroprevalence of Newcastle disease and other infectious diseases in backyard chickens at markets in Eastern Shewa zone, Ethiopia.

This study was conducted to estimate the seroprevalence of Newcastle disease (ND), Pasteurella multocida (PM) infection, Mycoplasma gallisepticum (MG) infection, and infectious bursal disease (IBD) and to assess the level of concurrent seropositivity during the dry and wet seasons of the year 2010. In total, 234 and 216 sera were collected during the dry and wet seasons, respectively, from unvaccinated backyard chickens at 4 live poultry markets in 2 woredas (districts) of Eastern Shewa zone, Ethiopia, and were tested using commercial ELISA kits. The overall seroprevalence of ND, PM, MG, and IBD was 5.9, 66.2, 57.7, and 91.9%, respectively, during the dry season, and 6.0, 63.4, 78.7, and 96.3%, respectively, during the wet season. The seroprevalence of MG was higher (P < 0.001) during the wet season than during the dry season and higher (P = 0.002) in Adami-Tulu-Jido-Kombolcha woreda (74%) than in Ada'a woreda (60%). Area and season had no significant effect on the seroprevalence of ND, IBD, and PM, indicating the widespread presence of those pathogens throughout the year in the study area. Of all the chickens tested, 85.6% had antibodies concurrently to more than one of the pathogens investigated. Birds were concurrently seropositive to more diseases during the wet season (median = 3) than during the dry season (median = 2; P = 0.002). As serology is not able to distinguish between strains, further studies are warranted to better understand the circulating strains, their interactions, and their economic effect on backyard poultry production in Ethiopia.

Serial plasma glucose changes in dogs suffering from severe dog bite wounds.

The objective of this study was to describe the changes in plasma glucose concentration in 20 severely injured dogs suffering from dog bite wounds over a period of 72 hours from the initiation of trauma. Historical, signalment, clinical and haematological factors were investigated for their possible effect on plasma glucose concentration. Haematology was repeated every 24 hours and plasma glucose concentrations were measured at 8-hourly intervals post-trauma. On admission, 1 dog was hypoglycaemic, 8 were normoglycaemic and 11 were hyperglycaemic. No dogs showed hypoglycaemia at any other stage during the study period. The median blood glucose concentrations at each of the 10 collection points, excluding the 56-hour and 64-hour collection points, were in the hyperglycaemic range (5.8- 6.2 mmol/l). Puppies and thin dogs had significantly higher median plasma glucose concentrations than adult and fat dogs respectively (P < 0.05 for both). Fifteen dogs survived the 72-hour study period. Overall 13 dogs (81.3 %) made a full recovery after treatment. Three of 4 dogs that presented in a collapsed state died, whereas all dogs admitted as merely depressed or alert survived (P = 0.004). The high incidence of hyperglycaemia can possibly be explained by the "diabetes of injury" phenomenon. However, hyperglycaemia in this group of dogs was marginal and potential benefits of insulin therapy are unlikely to outweigh the risk of adverse effects such as hypoglycaemia.

The effect of unrestricted milk feeding on the growth and health of Jersey calves.

This study was conducted to determine the effect of feeding high milk volumes on the growth rate, health and cross-sucking behaviour in group-fed Jersey calves. Three-day-old heifers (n = 120) in a seasonal calving dairy herd were randomly assigned to one of 6 treatment groups. Three groups received high milk volumes (HMV), consisting of ad libitum milk or milk replacer feeding twice a day, while 3 groups received restricted milk volumes (RMV), consisting of 2 l twice daily, during the pre-weaning period. After a pre-weaning period during which feeding was reduced to once daily, all calves were weaned at 42 days and monitored until 60 days of age. Adjusting for birth mass, birth date, dam parity and sire, average daily mass gain (ADG), both pre-weaning (days 0-42) and overall (days 0-60), was higher in HMV than in RMV calves (P < 0.001). After weaning, growth rates showed no differences and at 60 days of age the HMV calves maintained a 6.74 kg advantage in mean body mass (P < 0.001). The mean intake of dry starter feed was higher in RMV than in HMV calves. Overall feed conversion rate of HMV calves was 9.6 % better than RMV calves. However, the variable cost per kg mass gain was 12 % higher for HMV calves. In the RMV groups 75 % of calves showed cross-sucking behaviour pre-weaning and 18 % post-weaning, whereas in HMV calves the proportions were 2 % and 7 %, respectively. There was no significant effect of milk volume on the incidence of diarrhoea. We conclude that the feeding of high volumes of milk to Jersey calves has a positive effect on growth rate, without compromising health or reducing solid feed intake after weaning. However, the higher cost of such a feeding system may limit its implementation.

A questionnaire-based evaluation of the veterinary cordon fence separating wildlife and livestock along the boundary of the Kruger National Park, South Africa.

Veterinary cordon fences are used in Southern Africa to separate wildlife from domestic animals in order to prevent transmission of infectious diseases. Such fences are a control method recognized by the World Organization for Animal Health (OIE) for establishing disease-free zones in beef exporting countries. However, few studies have evaluated the ecological impact of these physical barriers or their effectiveness at a multispecies level. We examined the permeability of one such barrier, along 357 km of the western and southern boundary of the Kruger National Park (KNP) during 2007. Information was gathered using a semi-structured questionnaire implemented among 32 teams of fence maintenance workers. Data were analyzed to identify (a) the main causes of fence damage, (b) the seasonality, location and duration of fence repairs, (c) high permeability areas for elephant (Loxodonta africana), kudu (Tragelaphus strepsiceros), impala (Aepyceros melampus), buffalo (Syncerus caffer) and warthog (Phacochoerus africanus), and (d) the influence of fence electrification, rivers and elephant damage on the frequency of observation of wildlife species outside the KNP estimated during the year. Human and elephant damage were the most common reasons for fence repairs. Elephant and buffalo were the most and least common large mammal species reported observed outside the KNP (1076 and 162 reports/year), respectively. Cattle incursions into the KNP were also reported in 44% of the fence sections. Electrification of the fence was an important factor explaining differences in estimated wildlife species observations outside the KNP during the year. Correlations between estimations of observed species suggested that fence gaps created by elephants might be used by the other wildlife species. Estimated annual counts of kudu, impala and buffalo, but not warthog, were found to correlate with elephant observations. Negative binomial regression models were developed to explore the relationships between observed estimations of different wildlife species outside the KNP the fence, electrification of fence sections and the presence of watercourses, suggesting that kudu, impala and buffalo could use elephant induced fence damage to leave the KNP. The questionnaire was able to evaluate fence integrity and identify sections where integrity was sub-optimal for separating wildlife from domestic livestock species. If combined with more quantitative methods and applied on a routine basis, it could provide an efficient and cost-effective method for monitoring the effectiveness of physical barriers to contain wildlife within protected areas such as is the case with veterinary cordon fences in Southern Africa.

Influence of seminal plasma on fresh and post-thaw parameters of stallion epididymal spermatozoa.

Fresh and post-thaw parameters (motility, morphology and viability) of stallion epididymal spermatozoa that have been and have not been exposed to seminal plasma were evaluated, and directly compared to fresh and post-thaw parameters of ejaculated spermatozoa. Six sperm categories of each stallion (n=4) were evaluated for motility, morphology and viability. These categories were fresh ejaculated spermatozoa (Fr-E), fresh epididymal spermatozoa that had been exposed to seminal plasma (Fr-SP+), fresh epididymal spermatozoa that had never been exposed to seminal plasma (Fr-SP-), frozen-thawed ejaculated spermatozoa (Cr-E), frozen-thawed epididymal spermatozoa that had been exposed to seminal plasma prior to freezing (Cr-SP+) and frozen-thawed epididymal spermatozoa that had never been exposed to seminal plasma (Cr-SP-). Results show that seminal plasma stimulates initial motility of fresh epididymal stallion spermatozoa while this difference in progressive motility is no longer present post-thaw; and that progressive motility of fresh or frozen-thawed ejaculated stallion spermatozoa is not always a good indicator for post-thaw progressive motility of epididymal spermatozoa. This study shows that seminal plasma has a positive influence on the incidence of overall sperm defects, midpiece reflexes and distal cytoplasmic droplets in frozen-thawed stallion epididymal spermatozoa while the occurance of midpiece reflexes is likely to be linked to distal cytoplasmic droplets. Furthermore, seminal plasma does not have an influence on viability of fresh and frozen-thawed morphologically normal epididymal spermatozoa. We recommend the retrograde flushing technique using seminal plasma as flushing medium to harvest and freeze stallion epididymal spermatozoa.

Serial haematology results in transfused and non-transfused dogs naturally infected with Babesia rossi.

This prospective longitudinal study investigated the progression of haematological changes in 32 transfused and 54 non-transfused dogs naturally infected with Babesia rossi over the 1st 6 days following diagnosis and treatment. The effect of patient age on the results of complete blood counts was determined. Haematology data were analysed at presentation and at 24 hours, 3 days and 6 days after presentation. Dogs were treated with diminazene aceturate at diagnosis and a blood transfusion was given if deemed clinically required. Mildly to moderately regenerative normocytic normochromic anaemia was observed in all dogs throughout the study period. Transfused dogs more often had an inflammatory leukogram at presentation and at 24 hours, than dogs that were not transfused. In dogs with a left shift, a concurrent normal or decreased segmented neutrophil count was found more commonly than neutrophilia. Severe thrombocytopenia that resolved within a week was common. Blood transfusion alleviated the anaemia, but had no significant effect on white blood cell or platelet responses. Blood cell responses were not significantly influenced by age. In conclusion, the red blood cell and white blood cell responses were less than expected in dogs with babesiosis, given the degree of anaemia and inflammation present. The magnitude of thrombocytopenia and rapid return of the platelet count to normal suggested a possible immune-mediated mechanism for the thrombocytopenia.