SUMMARYFaeces samples from diarrhoeic and non-diarrhoeic lambs and goat kids aged 1-45 days were examined for enteric pathogens. Cryptosporidium parvum was detected in both diarrhoeic lambs (45 %) and goat kids (42%) but not in non-diarrhoeic animals. F5+ (K99+) and/or F41+ Escherichia coli strains were isolated from 26% and 22 % of the diarrhoeic lambs and goat kids, respectively, although these strains, which did not produce enterotoxins ST I or LT I, were found with similar frequencies in non-diarrhoeic animals. A F5-F41 -ST I' E. coli strain was isolated from a diarrhoeic lamb (0-6%). Verotoxigenic E. coli was isolated from both diarrhoeic and non-diarrhoeic lambs (4-1 % and 8&2 %, respectively) and there was no association between infection and diarrhoea. The prevalence of group A rotavirus infection in diarrhoeic lambs was very low (2 1 %). Groups A and B rotaviruses were detected in three (8-1 %) and five (13-5 %) diarrhoeic goat kids from two single outbreaks. Group C rotaviruses were detected in four non-diarrhoeic goat kids. An association of diarrhoea and infection was demonstrated only for group B rotavirus. Clostridium perfringens was isolated from 10-8 % of the diarrhoeic goat kids but not from non-diarrhoeic goat kids or lambs. Salmonella arizonae was isolated from a diarrhoeic goat kid (2-7 %) and the clinical characteristics of the outbreaks where these two latter enteropathogens were found different from the rest. Picobirnaviruses were detected in a diarrhoeic lamb. No coronaviruses were detected using a bovine coronavirus ELISA. No evidence was found of synergistic effect between the agents studied. Enteric pathogens were not found in four (8-7 %) and three (20%) outbreaks of diarrhoea in lambs and goat kids, respectively.

Abstract. Two blocking enzyme-linked immunosorbent assays (ELISAs) involving the use of monoclonal antibodies (MAb) as capture and detecting agents and an indirect fluorescence test (IFT) were used for the detection of porcine epidemic diarrhea virus (PEDV) antigen or its antibodies. In the ELISA for viral antigen detection, the blocking step is accomplished by incubation of fecal samples, in duplicate wells, with PEDVspecific positive or negative serum, whereas in the ELISA for antibody detection the blocking step is accomplished by incubation of serum samples with a gut-origin virus suspension. All the methods developed were used to monitor an experimental infection in piglets with the CV-777 strain of PEDV and a natural PED outbreak in a swine fattening unit. The antigen-detection ELISA was able to detect PEDV shedding for a longer time than have previously described methods. The blocking ELISA for antibody detection was able to detect the serum antibody response sooner after PEDV infection than did IFT.

Combinations of porcine respiratory coronavirus (PRCV) and either of two swine influenza viruses (H1N1 or H3N2) were administered intranasally and by aerosol to six-to eight-week-old specific pathogen:free pigs. The clinical responses, gross respiratory lesions and growth performances of these pigs were studied and compared with those of single (PRCV, H1N1 or H3N2) and mock-infected animals. PRCV infection caused fever, growth retardation and lung lesions, but no respiratory symptoms. Infection with swine influenza viruses caused rather similar, mild symptoms of disease, with H1N1 infection being the least severe. Combined infections with influenza viruses and PRCV did not appear to enhance the pathogenicity of these viruses. Furthermore, viruses were isolated more frequently from tissues and nasal swabs taken from 'single' than 'dual' infected animals, suggesting a possible in vivo interference between replication of PRCV and swine influenza virus.

In the Murcia region of south east Spain, epidemics of transmissible gastroenteritis-like disease have occurred in pigs every three years since 1980. In 1987 a sero-epidemiological survey was conducted to estimate the prevalence and spread of transmissible gastroenteritis virus (TGEV) infection among breeding pigs and farms, and to determine any association between the infection and herd size and geographical zone. The Murcia region was divided into four geographical zones and the farms were classified by size into four categories. The random sample was statistically representative of both the breeding stock and the farms in each geographical zone, and the analyses involved 6000 breeding pigs from 480 farms. The immunological techniques employed were the indirect ELISA and the blocking ELISA. The prevalence of seropositive breeding pigs was 1.27 +/- 0.28 per cent and the prevalence of infected farms was 5 +/- 1.94 per cent. On the infected farms, the prevalence of seropositive pigs ranged from 5 to 60 per cent. The infection occurred throughout the Murcia region, but a significant association (P < 0.01) was observed between the geographical zone and the prevalence of TGEV infection. Herds with > or = 50 breeding pigs had a greater prevalence (P < 0.01) of TGEV infection.

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