Re‐emergence of rabies virus maintained by canid populations in Paraguay

Paraguay has registered no human cases of rabies since 2004, and the last case in dogs, reported in 2009, was due to a variant maintained in the common vampire bat “Desmodus rotundus”. In 2014, a dog was diagnosed as positive for rabies with aggression towards a boy and all required measures of control were successfully adopted. Epidemiological investigation revealed that the dog was not vaccinated and had been attacked by a crab‐eating fox, “zorro” (Cerdocyon thous). The sample was diagnosed by the Official Veterinary Service of the Country and sent to the Center on Rabies Research from the University of São Paulo, Brazil, for antigenic and genetic characterization. A second sample from a dog positive for rabies in the same region in 2015 and 11 samples from a rabies outbreak from Asuncion in 1996 were also characterized. The antigenic profile of the samples, AgV2, was compatible with one of the variants maintained by dogs in Latin America. In genetic characterization, the samples segregated in the canine (domestic and wild species)‐related group in an independent subgroup that also included samples from Argentina. These results and the epidemiology of the case indicate that even with the control of rabies in domestic animals, the virus can still circulate in wildlife and may be transmitted to domestic animals and humans, demonstrating the importance of continuous and improved surveillance and control of rabies, including in wild species, to prevent outbreaks in controlled areas.     

Outbreak of foetal infection with bovine pestivirus in a central Queensland beef herd

OBJECTIVE: To describe a significant outbreak of foetal infection and subsequent losses due to bovine pestivirus on a 5200 ha beef breeding and fattening property in central Queensland. DESCRIPTION OF THE HERD: The affected herd consisted of 656 cows, including 269 recently purchased cows, and 221 heifers that were joined in December/January 1995/96. There were approximately 2500 cattle on the property. INVESTIGATION: Following the purchase of 269 cows in October 1995, which were mingled with the existing cow herd, losses were experienced due to foetal infection with bovine pestivirus. These losses were recorded between 1996 and 1999 as: reduced pregnancy rates, losses between pregnancy testing (midpregnancy) and branding (calves averaged 3 months-of-age), losses due to pneumonia and ill-thrift between branding and approximately 12 months-of-age, and losses due to ill-thrift and the chronic wasting form of mucosal disease thereafter. All surviving calves were tested for bovine pestivirus in 1997 at an average of 10 months. Fifty-three calves were identified as persistently infected with bovine pestivirus. A further 110 calf losses could reasonably be attributed to bovine pestivirus infection. Persistently infected cattle were always unthrifty compared to their virus negative counterparts. Only one persistently infected calf was identified, on the basis of severe ill thrift, in the 1997 birth cohort and none in 1998. CONCLUSIONS: This outbreak of foetal infection with bovine pestivirus resulted in significant production losses. These losses were recorded over the three years subsequent to the outbreak. Significant numbers of persistently infected calves were not evident among calves born in the two years after this outbreak.     

The Influence of Powdered Coconut Water (ACP‐318®) in In Vitro Maturation of Canine Oocytes

The objective of this study was to determine the influence of powdered coconut water (ACP‐318^®) diluted in high glucose (11.0 mm ) TCM199 in the achievement of nuclear in vitro maturation (IVM) of canine oocytes. Cumulus oocyte complexes (COCs) (n = 632) were randomly allocated into three experimental groups named as group 1 (control group), group 2 (5% powdered coconut water) and group 3 (10% powdered coconut water). The percentage of meiotic resumption (MR) (GVBD to MII) was 39.1% (81/207), 50.2% (108/215) and 46.6% (98/210) for groups 1, 2 and 3 respectively (p < 0.05). There were no differences in MR rates among groups 2 and 3. The medium with ACP‐318^® slightly enhanced the nuclear maturation of canine oocytes when a comparison was established with rates of maturation exhibited by oocytes in the experimental group 1 without ACP‐318^® (p < 0.05). The results suggest that oocytes’ nuclear morphology integrity and meiosis achievement were positively influenced when exposed to high glucose TCM199 supplemented with 5% powdered coconut water. Further investigation must be performed for a better understanding of powdered coconut water influence in cellular events during IVM of dog oocytes.     

Morphological aspects and histological effects of the attachment organ of Parabrachiella sp. (Copepoda: Lernaeopodidae) on the grey mullet,Mugil liza Valenciennes

The genus Parabrachiella Wilson, 1915 (Lernaeopodidae) is represented by copepods that are highly adapted to a parasitic way of life. In Argentina, only P. insidiosa var. lageniformis Heller, 1865, P. chevreuxii Van Beneden, 1891 and P. spinicephala Ringuelet, 1945 have been cited, but none of these have been reported on mugilids. Recently, other species of this genus were found attached to the nasal cavities of juvenile grey mullets, Mugil liza Valenciennes, from Samborombón bay, Buenos Aires province. In this study, the prevalence and mean intensity of the Parabrachiella sp. on grey mullet is investigated. In addition, the damage the parasite imposes on its hosts is examined through evaluation of histological sections and immunostaining for proliferative cell nuclear antigen (PCNA). The morphology of the parasite's bulla is described from light and scanning electron micrographs.     

A new monorchiid cercaria (Digenea) parasitising the purple clam Amiantis purpurata (Bivalvia: Veneridae) in the Southwest Atlantic Ocean, with notes on its gonadal effect.

An unnamed microcercous cercaria (Digenea: Monorchiidae), a parasite of Amiantis purpurata (Lamarck, 1818) (Bivalvia: Veneridae) and its corresponding metacercaria from the province of Buenos Aires and the Patagonian coast of the Southwest Atlantic Ocean, are described. The cercaria described in this paper differs from the three other monorchiid microcercous cercariae, i.e., Lasiotocus minutus (Manter, 1931), Lasiotocus elongatus (Manter, 1931), and Cercaria caribbea XXXVI Cable, 1956, mainly because of the extension of the excretory vesicle and the location of the ventral sucker. Cercariae artificially extracted from sporocysts encyst in a dish and form metacercariae enveloped by a gelatinous sac with two prolongations, which are used to adhere to the substratum. The monorchiid described in this paper has a life cycle similar to those of L. minutus and L. elongatus, although the adult stage of the present species is still unknown. Their larvae are similar in morphology and have venerid clams as their first hosts. The presence of a monorchiid larva is reported for the first time in the Southern Hemisphere. Its monthly prevalence rates, ranging from 0 to 25% (mean: 8.3%), are given from the Patagonian coast. The infection seems to cause castration as it was observed that during March through to May, when most gametes were produced in uninfected individuals, 81% of the infected individuals did not produce gametes.     

Hemibranch preference by freshwater monogeneans a function of gill area, water current, or both?

Differences in the occurrence of monogeneans on lamellae of fish gill arches were observed in this study. These differences were attributed to variations in water current on the gill surfaces or to greater area of certain arches. Two computer simulation programs based on gill area and water current were written to generate parasite metapopulations with clumped patterns. The results obtained were compared with true distributions of selected freshwater monogenean taxa. The combination of both theoretical models (gill area and water current) had greater explanatory power than either of the models alone.     

Vitrification of In Vitro-produced Bovine Embryos by Addition of Ethylene Glycol in One-step

The objective of this study was to simplify two-step addition of cryoprotectant for vitrification of bovine embryos by developing a one-step procedure. Survival was calculated as a percentage of non-vitrified controls developed from the same batch of oocytes. In experiment 1, bovine blastocysts were vitrified following one- or two-step addition of cryoprotectant. Exposure of embryos to cryoprotectant in one-step resulted in survival rates not significantly lower (p > 0.1) than those obtained by two-step addition (85% vs 98%, respectively). Based on these results, experiments 2-4 were designed to test one-step addition of cryoprotectant more rigorously. Experiment 2 exposed day 7 blastocysts to 6, 7 or 8 M ethylene glycol for 2.5 or 3.5 min. At 24 h post-vitrification, survival of embryos was similar, irrespective of ethylene glycol concentration or exposure time (6 M 38%, 7 M 51%, 8 M 59%; 2.5 min 54%, 3.5 min 45%). In experiment 3, blastocysts were exposed to 7 M ethylene glycol for shorter times (30 or 60 s); 30 s exposure resulted in decreased survival (8% vs 31%, p < 0.05). Experiment 4 concerned one-step addition of cryoprotectant to day 6 bovine morulae, exposed to 7 M ethylene glycol for 1 or 1.5 min. There was no difference in survival between exposure times of 1 or 1.5 min (28% vs 45%, respectively; p > 0.1). It is unclear why many embryos survive vitrification with one-step addition of cryoprotectant, but others do not. Although, one-step addition of cryoprotectant simplifies the vitrification procedure, survival rates were inadequate for routine cryopreservation of in vitro-produced bovine embryos.