A study of neonatal cryptosporidosis of foals in New Zealand

Abstract

AIM: To assess the occurrence of Cryptosporidium oocysts in faecal specimens from foals, and investigate an outbreak of neonatal cryptosporidiosis in foals revealed in the course of the study.

METHODS: Faecal specimens from foals received by a diagnostic veterinary laboratory in New Zealand between 2006 and 2007 were submitted to Massey University and tested microscopically for the presence of Cryptosporidium oocysts. The Cryptosporidium isolates in the oocyst-positive specimens were genetically identified to species level. In addition, specimen submission data from the participating laboratory for 2005–2007 were examined. In the course of the study, the identification of one Cryptosporidium-positive specimen triggered an on-farm investigation.

RESULTS: Twelve faecal specimens submitted by the participating laboratory between 2006 and 2007 were tested further, and three were positive for C. parvum. Specimen submission records indicated a total of 67 faecal specimens were tested for Cryptosporidium by the participating laboratory between 2005 and 2007; 12 (18%) were positive. The on-farm investigation on a broodmare farm revealed a high incidence of neonatal diarrhoea in foals; C. parvum was the only enteropathogen found in the faeces of 4/4 affected foals examined. The diarrhoea in all those foals was self-limiting, manifesting during the second week of life, resembling foal heat diarrhoea, and accompanied by a short but intense period of shedding oocysts.

CONCLUSIONS AND CLINICAL RELEVANCE: The fact that Cryptosporidium parasites were identified in 18% of faecal specimens from foals analysed for this agent in 2005–2007 by the participating laboratory indicated that infection with this agent in foals is not uncommon.

Collectively, the results of this and previous studies performed in New Zealand indicate C. parvum is a cause of diarrhoea in newborn foals, potentially accounting for a proportion of cases empirically diagnosed as foal heat diarrhoea. It is therefore advisable to take precautions when handling diarrhoeic foals, until this potentially zoonotic agent is ruled out in the laboratory.     

Quantification of historical livestock importation into New Zealand 1860–1979

AIMS: To quantify the numbers of live cattle, sheep and poultry imported into New Zealand and, where possible, their country of origin from 1860 to 1979.

METHODS: Information on the origin and number of live animal importations into New Zealand was collected for cattle, sheep and poultry for the period 1868–1979 from the annual reports compiled by the New Zealand Registrar General's Office, Government Statistician's Office, Census and Statistics Office, Census and Statistics Department, Customs Department and Department of Statistics. Census data from 1851 to 1871 were also used to estimate the livestock population during this period. The number of animals imported and the mean population for each species in a decade were determined, and the major countries of origin were identified.

RESULTS: A large number of cattle (53,384) and sheep (604,525) were imported in the 1860s, and then there was a marked reduction in importations. Live poultry were imported in relatively small numbers (20,701) from 1880 to 1939, then 1,564,330 live poultry were imported between 1960 and 1979. Australia was the predominant country of origin for sheep between 1868 and 1959 (51,347/60,918; 84.3%) and of cattle between 1868 and 1979 (10,080/15,157; 66.5%). Only 6,712 (11.0%) sheep and 3,909 (25.8%) cattle were imported from the United Kingdom over the same periods, and even fewer from other countries.

CONCLUSIONS: The collated data and historical reports show that from 1860 to 1979 Australia has been the main source of livestock introduced into New Zealand. The pattern of importation showed that large numbers of cattle and sheep were initially imported in the 1860s, probably in response to rapid agricultural expansion. Thereafter importations continued at much reduced numbers. In contrast, relatively small numbers of poultry were introduced until the 1960s when large numbers were imported as part of the development of a modern high-production industry. The overall pattern for both cattle and sheep was of a bottleneck event, as initially a relatively limited number of animals arrived from outside populations, followed by population expansion with ongoing but limited immigration (admixture). Investigation into the genetic population structure of New Zealand's cattle and sheep, as well as their host-associated microorganisms, could reflect the impact of these early historical events.     

In Vitro Maturation and Fertilization of Buffalo Oocytes: Effects of Storage of Ovaries, IVM Temperatures, Storage of Processed Sperm and Fertilization Media

Studies were conducted to examine the possibility of preserving slaughterhouse‐derived buffalo ovaries at 4°C for 0 (control), 12 and 24 h to maintain the developmental competence of the oocytes (experiment 1), to assess the effect of incubation temperature during oocyte maturation on rates of in vitro maturation (IVM) and in vitro fertilization (IVF) of buffalo oocytes and embryo development (experiment 2), and to examine the effect of storage at 25°C for 0 (control), 4 and 8 h of frozen–thawed buffalo sperm and BO and H‐TALP as sperm processing and fertilization media on cleavage and embryo development in vitro of buffalo oocytes (experiment 3) in order to optimize the IVF technology in buffalo. Results suggested that storage of ovaries at 4°C for 12 or 24 h significantly (p < 0.05) reduced the developmental potential of oocytes. Incubation temperatures during the IVM influenced the fertilization rate but had no significant effect on maturation and subsequent embryo development. The incubation temperature of 38.5°C during IVM was found to be optimum for embryo production in vitro. Storage of frozen–thawed sperm at 25°C for 8 h significantly (p < 0.05) decreased its ability to cleave the oocytes. Sperm processed in BO medium had significantly (p < 0.05) higher ability to cleave the oocytes than the H‐TALP medium.     

L-2-hydroxyglutaric Aciduria in Two Female Yorkshire Terriers

Two female Yorkshire terrier puppies were presented with generalized tonic-clonic seizures and ataxia. MRI revealed bilaterally symmetrical, diffuse regions of gray matter hyperintensity on T2-weighted and fluid-attenuated inversion recovery sequences. Urinary organic acids were quantified by gas chromatography-mass spectroscopy and were consistent with a diagnosis of L-2-hydroxyglutaric aciduria (L2HGA). The L2HGDH gene encodes for the enzyme L-2-hydroxyglutarate dehydrogenase, which helps break down L-2-hydroxyglutaric acid. In both puppies described in this report, a homozygous mutation at the translation initiation codon of the homolog canine L2HGDH gene was detected (c.1A>G; p.Met1?), confirming the diagnosis of L2HGA at the DNA level. Canine L2HGA is caused by more than one mutation of L2HGDH, as reported in humans.     

Simplified preparation of a specific S. enteritidis antigen for ELISA and other immunological techniques

This study was conducted to prepare a specific S. enteritidis antigen (FG-Antigen) for the serological detection of S. enteritidis infections in chicken flocks. This antigen (FG-Antigen) consistent mainly of the flagellar fraction H:g and partly of the fimbrial fraction SEF14 from a S. enteritidis-phage type 4 strain. The initial steps followed in the preparation of this antigen were conducted based on a previously described procedure, which involved the application of heat at 60 degrees C. The purification process (filtration and concentration) enabled the exclusion of the cross-reaction causing LPS antigens from the preparation and allowed the retention of S. enteritidis-specific antigens composed of fimbria and H:g fractions. As a result, no cross-reaction with S. typhimurium nor with S. gallinarum was exhibited by the prepared FG-antigen. To characterize and determine its specificity, the following laboratory tests were conducted: indirect ELISA, immunoblotting and a SEF14 agglutination test. In these examinations, rabbit and chicken reference sera as well as chicken field sera and absorbed hyperimmune sera against H:g-carrying serovars were used.