Prevalence of Streptococcus dysgalactiae subsp. equisimilis and S. equi subsp. zooepidemicus in a sample of healthy dogs, cats and horses.

AIMS: To estimate the prevalence of ß-haemolytic Lancefield group C streptococci in healthy dogs, cats and horses; to determine if frequent contact with horses was associated with isolation of these species from dogs and cats; and to characterise recovered S. equi subsp. zooepidemicus isolates by multilocus sequence typing. METHODS: Oropharyngeal swabs were collected from 197 dogs and 72 cats, and nasopharyngeal swabs from 93 horses. Sampling was carried out at the Massey University Veterinary Teaching Hospital, on sheep and beef farms or on premises where horses were present. All animals were healthy and were categorised as Urban dogs and cats (minimal contact with horses or farm livestock), Farm dogs (minimal contact with horses) and Stable dogs and cats (frequent contact with horses). Swabs were cultured for ß-haemolytic Streptococcus spp. and Lancefield group C streptococcal subspecies were confirmed by phenotypic and molecular techniques. RESULTS: Of the 197 dogs sampled, 21 (10.7 (95% CI= 4.0-25.4)%) tested positive for S. dysgalactiae subsp. equisimilis and 4 (2.0 (95% CI=0.7-5.5)%) tested positive for S. equi subsp. zooepidemicus. All these isolates, except for one S. dysgalactiae subsp. equisimilis isolate in an Urban dog, were from Stable dogs. S. dysgalactiae subsp. equisimilis was isolated from one Stable cat. Of the 93 horses, 22 (23.7 (95% CI=12.3-40.6)%) and 6 (6.5 (95% CI=2.8-14.1)%) had confirmed S. dysgalactiae subsp. equisimilis and S. equi subsp. zooepidemicus isolation respectively. Isolation of S. dysgalactiae subsp. equisimilis from dogs was associated with frequent contact with horses (OR=9.8 (95% CI=2.6-72.8)). Three different multilocus sequence type profiles of S. equi subsp. zooepidemicus that have not been previously reported in dogs were recovered. CONCLUSIONS AND CLINICAL RELEVANCE: Subclinical infection or colonisation by S. equi subsp. zooepidemicus and S. dysgalactiae subsp. equisimilis occurs in dogs and further research on inter-species transmission and the pathogenic potential of these Lancefield group C streptococci is needed. Complete speciation of ß-haemolytic streptococci should be recommended in clinical cases and the possible exposure to horses and their environment should be considered in epidemiological investigations.

Avian polyomavirus identified in a nestling Gouldian finch (Erythrura gouldiae) in New Zealand.

Abstract CASE HISTORY: Four 4-5-month-old nestlings and one adult in a commercial aviary of 53 Gouldian finches (Erythrura gouldiae) died over a 2-week period in July 2000. PATHOLOGICAL FINDINGS: One nestling was necropsied and showed bronze-tinged skeletal muscles, a swollen liver with haemorrhagic margins and numerous haemorrhages on serosal surfaces. The histological lesions included multifocal hepatic necrosis and haemorrhage associated with the presence of large clear or basophilic intranuclear inclusions in hepatocytes and Kupffer cells suggestive of avian polyomavirus infection. Similar inclusion bodies were present in splenic histiocytes. MOLECULAR BIOLOGY: DNA was subsequently extracted from archived portions of liver, spleen, gizzard, heart, lung and kidney. A broad spectrum nested PCR was used to detect polyomavirus which sequence analysis confirmed as finch polyomavirus. DIAGNOSIS: Avian polyomavirus. CLINICAL RELEVANCE: Avian virus infections such as polyomavirus should be suspected in cases of sudden death in nestlings, particularly in susceptible species such as psittacine and passerine birds. The archiving of tissues from unconfirmed disease outbreaks provides a valuable resource for retrospective investigations.

Voltage-current relationship for flashlamps: an empirical approach.

This paper presents the results of an empirical study of the voltage-current relationship of flashlamps. It is shown that the Goncz and Marotta relationships are limited in that they can only be used in certain current density regimes. Based on empirical data, a generalized empirical voltage-current relationship is proposed. In particular, the generalized form is found to be a voltage-current relationship with a power factor. This power factor is found to be a function of the current density of the flashlamp. The relationships used in the past are found to fit this generalized form according to their respective current density regimes.