Prevention of Toxoplasma gondii abortion in goats by vaccination with oocysts of Hammondia hammondi

Nineteen does (female goats) were dosed with 500,000 oocytes of Hammondia hammondi prior to breeding. At about 90 days of gestation these, and 18 uninoculated does were challenged with 25,000 Toxoplasma gondii oocysts. The 19 H. hammondi--inoculated does produced 26 live and one dead kid (newborn goat). The 18 does not given H. hammondi produced 12 live and 19 dead kids. However, examination of all of the kids by isolation of T. gondii in mice, serology and histology revealed that they were all infected with T. gondii. Thus, while H. hammondi "vaccination" is protective against the deleterious effects of T. gondii on pregnant does, perhaps by reducing the severity of placental lesions, it does not prevent foetal infection.     

Seroprevalence of Toxoplasma gondii in mainland and sub-Antarctic New Zealand sea lion (Phocarctos hookeri) populations

AIMS: To investigate the seroprevalence of antibodies to Toxoplasma gondii in New Zealand sea lions (Phocarctos hookeri), as a potential contributor to reproductive failure.

METHODS: Archived sera were sourced from New Zealand sea lions from two recolonising mainland populations in the Otago Peninsula (n=15) and Stewart Island (n=12), as well as a declining population at Enderby Island (n=28) in the New Zealand sub-Antarctic. Sera were tested for antibodies to T. gondii using a commercially available ELISA (with samples considered positive if the sample to positive ratio was?>30%), and latex agglutination test (LAT; with titres ≥1:32 considered positive). Western blot analysis was used to validate the results of a subset of 14 samples.

RESULTS: Five samples from sea lions in mainland locations were confirmed positive for antibodies to T. gondii. Two adult females exhibited high LAT antibody titres (min 1:2048, max 1:4096) on both occasions when sampled 1 and 2 years apart, respectively. No animals from Enderby Island were seropositive.

CONCLUSIONS: Toxoplasma gondii infection is unlikely to be a major contributor to poor reproductive success in New Zealand sea lions. However, continued surveillance is pertinent to assess subclinical and clinical impacts of the parasite on these threatened populations. The commercial tests evaluated here, with further species-specific threshold refinement could provide a fast, inexpensive and reliable indicator of T. gondii exposure in New Zealand sea lions.     

Effects of food deprivation on white muscle energy reserves in rainbow trout (Oncorhynchus mykiss): the relationships with body size and temperature

The relationship between body size and the depletion of white muscle metabolites (e.g., PCr, ATP, glucose and glycogen) was examined in two sizes (30 or 700 g) of rainbow trout deprived of food for one, four or seven days at either 5 or 15 °C. Following 7 days of food deprivation at 15 °C, the levels of muscle glycogen decreased by approximately 50% in small fish relative to control values (i.e., day 1). In comparison, small fish acclimated to cold temperatures did not exhibit a significant reduction of muscle glycogen over the seven day fasting regime. In contrast to small fish, the levels of white muscle glycogen in large fish remained unchanged after food deprivation, regardless of acclimation temperature. A seven day deprivation of food also resulted in a 50% depletion of white muscle glucose concentrations in small and large fish acclimated to warm temperatures, but there were no significant changes in this variable in fish acclimated to cold temperatures. In contrast to the negative effects of food deprivation on white muscle glycogen and glucose levels, the concentrations of white muscle PCr and ATP were not greatly affected by food deprivation under any of the experimental conditions. Taken together, these results clearly show that food deprivation can have an important influence on the storage of energy metabolites for anaerobic energy production, particularly in small fish at warm temperatures. In the future, it may be very important to consider the physiological effects of short-term food deprivation when interpreting results from studies in which fish have been fasted prior to treatments such as exercise.     

Age Effects on Blood Gas,Spirometry, Airway Reactivity,and Bronchoalveolar Lavage Fluid Cytology in Clinically Healthy Horses

Background

Despite the increasing number of geriatric horses attended by veterinarians, there is a lack of understanding of aging‐related changes on the respiratory system of horses.

Objective

To identify aging‐related changes on the respiratory function and bronchoalveolar lavage fluid (BALF) cytology of horses.

Animals

Fifteen healthy young adult (2–11 years) and 16 healthy aged (≥20 years) horses.

Methods

The respiratory system was examined by measurement of arterial blood gases (ABG), use of respiratory inductive plethysmography (RIP) for assessment of breathing pattern and ventilatory parameters, histamine bronchoprovocation, and BALF cytology.

Results

No significant differences were detected with regard to values obtained by ABG or bronchoprovocation of young adult and aged healthy horses. In aged horses, there were significant differences in mean ± SD of the following parameters when compared to young horses: prolonged expiratory time (Te) measured by RIP (3.9 ± 1.5 s versus 3.0 ± 0.6 s), decreased percentage of alveolar macrophages (40.6 ± 11.3% versus 53.5 ± 9.6%), and increased percentage of lymphocytes (53.4 ± 9.5% versus 43.9 ± 11.0%). No correlations between airway reactivity and ventilatory parameters, ABG, or BALF cytology were found in this asymptomatic population.

Conclusions

These results suggest that aging does not cause changes in the results obtained by ABG, most RIP‐derived variables, and bronchoprovocation in the horse. A decreased percentage of macrophage and an increased percentage of lymphocytes in the BALF cytology may be expected in the asymptomatic geriatric horse and may be a result of aging.     

Genetic diversity,phylogenetic position and morphometric analysis of Astacus colchicus (Decapoda,Astacidae): a new insight into Eastern European crayfish fauna

The phylogeny of European crayfish fauna, especially with respect to Eastern European species, is still far from being completely resolved. To fill this gap, we analyzed most of the European crayfish species focusing on the phylogenetic position of the endemic crayfish Astacus colchicus, inhabiting Georgia. Three mitochondrial and one nuclear marker were used to study evolutionary relationships among European crayfish species, resulting in the unique phylogenetic position of A. colchicus indicating independent species status to A. astacus. Phylogenetic analyses revealed a deep molecular divergence of A. colchicus in comparison to A. astacus (6.5–10.9% in mtDNA and 1.1% in nDNA) as well as to Pontastacus leptodactylus and P. pachypus (5.5–10.0% in mtDNA and 1.4–2.4% in nDNA). Absent ventral process on second male pleopod and abdominal somites II and III with pleura rounded lacking prominent spines clearly indicate taxonomic assignment to the genus Astacus; however, the species is distributed almost in the middle of Ponto-Caspian area typical by occurrence of the genus Pontastacus. Several morphological indices linked to head length, carapace, and total body length and width were found to demonstrate apparent differences between A. colchicus and A. astacus. Although this study provides a novel insight into European crayfish phylogeography, we also point out the gaps in comprehensive study of the P. leptodactylus species complex, which could reveal details about the potential species status of particular species and subspecies within this genus.     

Dermatosparaxis in two White Dorper lambs

Abstract

CASE HISTORY AND CLINICAL FINDINGS: Two White Dorper lambs from the North Island of New Zealand, 2 and 4 weeks of age, were presented with large skin flaps hanging from the flanks, separation of skin from the subcutis over mobile joints, and de-gloving injuries of the limbs and tail. The lambs were subject to euthanasia on humane grounds.

PATHOLOGICAL FINDINGS: Large skin tears with associated haemorrhage, periarticular S/C oedema and generalised skin fragility were observed in both lambs at post-mortem examination. Histology of the affected skin revealed diffuse hyalinisation of dermal collagen compared with control lambs, protein-filled peri-adnexal clefts and areas of deep dermal and S/C granulation tissue consistent with previous separation of skin from the subcutis. Analysis of hair follicles, collected from one of the lambs, using a commercially available genetic test in Australia was consistent with the lamb being homozygous for the mutation responsible for ovine dermatosparaxis.

DIAGNOSIS: Likely dermatosparaxis.

CLINICAL RELEVANCE: These findings strongly suggest that the mutation responsible for dermatosparaxis in White Dorper sheep is present in New Zealand. Dermatosparaxis should be considered when investigating skin fragility in lambs with White Dorper genetics. Confirmation of the disorder is possible through genetic analysis of hair follicles.     

Naturally occurring and experimental Stachys arvensis (staggerweed) toxicity in lambs in New Zealand

Stachys arvensis (staggerweed) is a common, widely distributed weed of cultivated and waste land with the potential to intoxicate sheep. Two naturally occurring outbreaks of suspected staggerweed toxicity in the lower North Island were investigated. Affected lambs had been recently moved onto staggerweed-contaminated Brassica spp. crops. In total, 150/1,200 (13%) lambs developed hindlimb paresis, a fine generalised muscular tremor, and hunched posture. When forced to move, many became recumbent. Most lambs recovered within 48 h of removal from staggerweed, although a few developed clinical signs again when transported 2–3 weeks later. Grossly, affected lambs had large amounts of staggerweed plant material and seeds within the rumen. Histopathology showed mild, multifocal degeneration of the white matter tracts of the central nervous system (CNS), most commonly in the ventral funiculi of the spinal cord, and acute, mild to moderate, multifocal degeneration of skeletal muscles. Creatine kinase (CK) activity in serum was mildly to markedly elevated in affected lambs. In a feeding trial, ten 10-month-old Romney lambs were randomly assigned to equal treatment and control groups. Treated lambs were drenched with a liquid extract of staggerweed once daily for 7 days. Three of five treated lambs developed mild exercise intolerance, and 1/5 displayed mild paresis of the hindlimbs, slightly crouched hindlimb stance, and shortened gait, on days 6 and 7. Histologically, 4/5 treated lambs had degeneration in white matter tracts of the CNS, indistinguishable from those seen in the lambs in the outbreak, and in 1/5 lambs there was scattered regeneration of skeletal muscle. CK activity in serum in treated lambs was not significantly higher than that in control lambs. None of the control lambs developed significant clinical signs, histological changes or increases in CK activity in serum. The clinical signs and lesions observed in both the outbreaks and feeding trial were similar to those previously described in studies in Australia, with the exception that myodegeneration was more prominent in the outbreaks in New Zealand. Further characterisation of the pathogenesis of staggerweed toxicity and its potential role as a food safety hazard will be facilitated through identification of the toxic principle(s).