Percutaneous ultrasound-guided cholecystocentesis in cows.

A method was developed for percutaneous ultrasound-guided cholecystocentesis in cattle. The procedure was performed on the right side in the 9th, 10th, or 11th intercostal space of 30 cows. Of the 30 cows, 20 were slaughtered 24 hours after cholecystocentesis and the remaining 10 cows were slaughtered after a 10-day observation period. Changes in the peritoneum and gallbladder wall, observed at slaughter, were minimal. During the 10-day observation period, general behavior, attitude, and appetite of the 10 cows were normal. A transient, slight increase in rectal temperature was observed in 6 cows at 4, 5, or 8 days after cholecystocentesis. Total and differential WBC counts and total protein and fibrinogen concentrations, determined daily, were all within normal ranges. Bile samples from 20 cows were examined microscopically and biochemically. Fasciola hepatica and Dicrocoelium dendriticum eggs were observed in bile from 7 and 12 cows, respectively. Fecal examination revealed F hepatica eggs in 4 cows; D dendriticum eggs were not identified in any of the fecal samples. In 1 cow, F hepatica eggs were observed in the feces, but not in the bile. Bile acids concentration in bile varied from 12.5 to 68.5 mmol/L (mean +/- SD, 45.3 +/- 3.05 mmol/L) and in serum from 3.8 to 281.0 mumol/L (41.6 +/- 17.24 mumol/L). Negative correlation was obtained between bile acids concentration in bile and that in serum (r = -0.60, P less than 0.01). It was concluded that percutaneous ultrasound-guided cholecystocentesis in cows is a safe procedure and that microscopic and biochemical examinations of obtained bile can be useful diagnostic aids.     

The problem of escalating resistance of Haemonchus contortus to the modern anthelmintics in South Africa

During the past decade in South Africa there has been a continual increase in sheep of strains of gastrointestinal helminths resistant to the modern anthelmintics. Five strains of Haemonchus contortus are described in this paper. Despite the fact that 2 of the 5 strains were tested for susceptibility only to ivermectin, a total of 10 instances of resistance were found. Four of the 5 strains were resistant to ivermectin, 2 to closantel, 2 to rafoxanide and 2 to the benzimidazoles. One of these strains was concurrently resistant to 3 different anthelmintic groups, namely, the ivermectins, the benzimidazoles and the salicylanilides. Resistance to ivermectin developed in 2 strains of H. contortus after a history of only 3 treatments with this compound in one instance and 11 treatments in the other. In the latter case drenching with ivermectin was well interspersed with that of other anthelmintics. This rapid development of resistance suggests that there may be cross-resistance between ivermectin and another anthelmintic group. Two of the ivermectin resistant strains were recovered from separate properties in the south-western Cape Province, where Ostertagia circumcincta, which is usually the dominant parasite in this region, was virtually eliminated by the anthelmintic treatment. On each of these properties it was apparently replaced by a resistant strain of H. contortus. A serious threat to control is the dissemination of worm strains with multiple resistance to anthelmintics. The strain of H. contortus resistant to 3 anthelmintic groups has already been widely dispersed, as the farmer concerned suddenly decided to give up farming with sheep and to sell his flock.     

Effect of stocking density on vegetation and animal performance within the semi-arid shrublands of the Karoo,South Africa

As the primary land use in the Karoo, extensive small-stock farming contributes significantly towards the agricultural economy of the region. However, the sustainability of this practice has been questioned for many years. This led to the establishment of a long-term stocking-density trial in 1988 at the Carnarvon Research Station. The trial was designed on a three-camp rotational grazing system under four stocking densities (8, 7, 5.5 and 4 ha SSU^–1). Following continuous treatment over 28 years, the results from a once-off assessment in February 2016 portrayed no significant differences between treatments with regard to plant height, cover, species diversity, ecological and grazing index scores. Animal production varied among treatments where the mean production per hectare was found to be the highest under the high stocking-density treatment. Due to the absence of historical data, the results from this study are not conclusive with regards to changes in the vegetation dynamics over time and therefore does not lend itself to making conclusions concerning stocking densities. It can, however, be concluded that the vegetation of the Western Upper Karoo is remarkably resilient to the perceived higher stocking densities set at the time, on condition that an appropriate grazing management strategy is applied.     

Zoonotic origin and transmission of Middle East respiratory syndrome coronavirus in the UAE

Since the emergence of Middle East respiratory syndrome coronavirus (MERS‐CoV) in 2012, there have been a number of clusters of human‐to‐human transmission. These cases of human‐to‐human transmission involve close contact and have occurred primarily in healthcare settings, and they are suspected to result from repeated zoonotic introductions. In this study, we sequenced whole MERS‐CoV genomes directly from respiratory samples collected from 23 confirmed MERS cases in the United Arab Emirates (UAE). These samples included cases from three nosocomial and three household clusters. The sequences were analysed for changes and relatedness with regard to the collected epidemiological data and other available MERS‐CoV genomic data. Sequence analysis supports the epidemiological data within the clusters, and further, suggests that these clusters emerged independently. To understand how and when these clusters emerged, respiratory samples were taken from dromedary camels, a known host of MERS‐CoV, in the same geographic regions as the human clusters. Middle East respiratory syndrome coronavirus genomes from six virus‐positive animals were sequenced, and these genomes were nearly identical to those found in human patients from corresponding regions. These data demonstrate a genetic link for each of these clusters to a camel and support the hypothesis that human MERS‐CoV diversity results from multiple zoonotic introductions.