Enterotoxigenic Escherichia coli diarrhea of travelers: a prospective study of American Peace Corps volunteers

Travelers' diarrhea was studied prospectively in a group of 39 American Peace Corps Volunteers (PCVs) during their first five weeks in Kenya. Twenty-seven developed diarrheal disease and 12 remained well. Multiple episodes were documented in 11 of the symptomatic volunteers. Enterotoxigenic Escherichia coli of many serotypes producing heat-labile and/or heat-stable enterotoxin were isolated from 17 of the 27 volunteers with diarrhea and from 1 of the 12 well volunteers. The enterotoxigenic E. coli were more likely to be antibiotic sensitive than the non-enterotoxigenic E. coli. A serum antibody rise to the heat-labile toxin (LT) was detected in six symptomatic volunteers, five of whom had a positive culture for LT-producing E. coli, and from one asymptomatic, culture negative volunteer. Salmonella cubana was isolated from two volunteers, and three volunteers had serologic evidence of infection with human reovirus-like (rotavirus) agent. This study confirms the role of enterotoxigenic E. coli as a major cause of travelers' diarrhea and suggests that the disease is similar in widely separated geographic areas.

Enteropathogens associated with pediatric diarrhea in Mexico City

Enteropathogens were investigated as possible agents in pediatric diarrhea occurring in Mexico City during the summer of 1975. Pathogens were identified in 47 (76%) of 62 cases. Rotavirus particles were detected in 16 cases. Enterotoxigenic Escherichia coli was detected in 29 cases; 11 were positive for heat-labile enterotoxin and 18 were positive for only the heat-stable form of enterotoxin. Multiple pathogens were found simultaneously in 15 (24%) of the study population. This study indicates that the etiology of pediatric summertime diarrhea in Mexico City is diverse. ETEC and RV were the most frequently encountered pathogens, yet they frequently occurred together and with other pathogens. ST-only strains of toxigenic E. coli were as frequently recovered as LT-E. coli suggesting that both forms of ETEC must be sought in future field studies.

Culicoides, the vector of epizootic hemorrhagic disease in white-tailed deer in Kentucky in 1971

The biting gnat, Culicoides variipennis (Coquillett), was shown to be a vector of epizootic hemorrhagic disease (EHD) in white-tailed deer, Odocoileus virginianus, in Kentucky because of virus isolations from parous females. Epidemiological evidence showed a close relationship of this vector to the animal host during an outbreak of EHD in penned deer. Larval breeding sites of C. variipennis were found and C. variipennis was the most abundant biting fly present during the outbreak. Females of C. variipennis were commonly observed biting deer, swine, cattle and, occasionally, man.

[Infantile diarrhea and rotavirus (author's transl)]

The acute and convalescent sera of 328 children with acute enteritis were checked with the bovine diarrhea virus as antigen in complement fixation test. 13% had a seroconversion. Some cases were associated with skin rashes or signs of respiratory infection.

Infectious tenosynovitis in commercial White Leghorn chickens

Infectious tenosynovitis was diagnosed in three separate outbreaks in a commercial White Leghorn hens, though not previously reported in adult White Leghorns (3). Clinically affected flocks had decreased production and increased daily mortality, with many hens showing signs of the so called "cage-fatigue bluecomb" syndrome. Most sick birds had lesions typical of infectious tenosynovitis, with pronounced cyanosis and dehydration. Dead birds had signs of acute septicemia. The course of the disease (about 8 weeks) was not altered by the medicinal regimens tried. Young laying-age flocks were most seriously affected. Production losses averaged 15 to 20%, and mortality reached 5% per month during the recovery phase.

REOVIRUS-LIKE AGENT ASSOCIATED WITH NEONATAL DIARRHEA IN PRONGHORN ANTELOPE

Reovirus-like particles were demonstrated by negative stain electron microscopic examination of the feces from antelope fawns with diarrhea. Fluorescent antibody tests on frozen sections of ileum from one dead antelope fawn and immunoelectron microscopy tests on feces from two live fawns provided evidence that the antelope agent was serologically related to the neonatal calf diarrhea reovirus-like agent.

Human reovirus-like agent as the major pathogen associated with "winter" gastroenteritis in hospitalized infants and young children

We found a human reovirus-like agent in the stools of 42 per cent of 143 infants and young children hospitalized with acute gastroenteritis between January, 1974, and June, 1975. Half the patients studied by electron microscopy and serologic technics had evidence of infection with the agent. The infection had a seasonal pattern: 59 per cent of those admitted during the cooler months (November to April) shed the agent, with a peak of 78 per cent in December, 1974, and January, 1975, combined. None of the patients admitted during the warmer months (May to October) shed the agent. None of 275 Escherichia coli isolates from 32 patients with diarrhea produced heat-labile enterotoxin, whereas 17 of the 32 had evidence of infection with the reovirus-like agent. In addition, 14 of 40 parents of 37 patients with diarrhea associated with the reovirus-like agent were also infected, but most infectious were inapparent. This agent appears to be the major cause of diarrheal illness in the young during the cooler months.

Rotavirus enteritis in the West Midlands during 1974

During 1974 in the West Midlands of England, 38% of children less than 6 years old with enteritis were excreting rotaviruses. Children aged from 6 months to 3 years were those most commonly infected. Rotavirus infections were most common during winter with only a few sporadic cases during summer. A possible pathogen was detected in 59% of patients examined.

An outbreak of a hemorrhagic disease in white-tailed deer in Kentucky

In 1971, an outbreak of a hemorrhagic disease occurred in captive and free-ranging white-tailed deer (Odocoileus virginianus) in Mammoth Cave National Park, Kentucky, Clinical signs and gross pathological lesions were consistent with those of epizootic hemorrhagic disease and bluetongue, as were serological and histopathological findings for samples sent to other laboratories. The infection rate among the 104 captive deer was 88-92%, and that among the free-ranging Park deer appeared to be similar. Mortality was negligible in the Park deer, but 65 (62%) of the captive deer died. The deaths were bimodally distributed over a 36-day period, and the mortality rate decreased from 97-100% for deer clinically ill during the first 17 days of the outbreak to 58% for deer first exhibiting clinical signs on day 16 or later. Mortality was equal in males and females, but less in yearlings than among fawns or adults. Winter mortality among survivors of the initial outbreak was associated with low ambient temperatures and sometimes fungal and bacterial abscesses, possibly sequelae or complications of the hemorrhagic disease. The pregnancy and birth rates among surviving does appeared to be normal.

Viral enteritis of calves

Calf diarrhoea is an important cause of economic loss. The aetiology of the disease is considered with particular reference to the role of viruses. Although many microbial organisms have been associated with the disease, there is doubt concerning their true role as causative agents. Two viruses, neonatal calf diarrhoea reovirus-life agent and calf coronavirus, have been discovered recently which appear to play an important role in many cases of diarrhoea and the evidence for considering them to be primary causes of the disease is discussed.

Infectious bursal disease in New Brunswick

A flock of four week old chickens experienced a disease of sudden onset in which the only symptoms were those of depression shortly before death, and in which the predominant histological lesion was necrosis of lymphocytes in the bursa of Fabricius.A virus, designated strain Sk-1, was isolated from pooled bursal tissue of affected birds and was serologically identified as a strain of the infectious bursal agent. This virus was chloroform resistant, did not hemagglutinate guinea pig or chicken erythrocytes and did not produce a cytopathic effect in chick embryo tissue cultures. Equivocal results were obtained in filtration studies but the agent was less than 100nm in diameter. Four week old chicks inoculated with strain Sk-1 developed microscopic lesions in the bursa of Fabricius which were similar to those seen in the original field specimens. Inoculated chick embryos exhibited characteristic macroscopic lesions and necrosis of vascular tissue was a common histological change.A limited serological survey of local poultry flocks indicated that infection by this agent had occurred in four of the ten flocks examined.

Sero-epidemiological study of reovirus infection amongst the normal population of the Chandigarh area--northern India

Two hundred and sixty-four samples of sera obtained from normal healthy persons belonging to different age groups were examined for haemagglutination-inhibiting antibodies against reovirus types 1–3 to assess the prevalence of reovirus infection in the northern part of India.

Reovirus infection appeared as early as 6 months to 1 year of age. With reovirus types 1 and 2, the maximum incidence of 67 and 48% respectively occurred by the age of 10–20 years, whereas with type 3 infection the maximum incidence (73%) was reached by the age of 25 years. The incidence of reovirus type 2 infection in all the age groups was remarkably low in this series. A drop in the incidence of reovirus type 2 infection was also noticed after the age of 20 years.

The difference in geometric mean titre of antibody in different ages against reovirus type 2 was highly significant, suggesting probably that most of the infection occurred by the age of twenty years. The difference in the geometric mean value of the titres of antibody against types 1 and 3 was not significant in different age groups. The levels of antibody against types 1 and 3 in all the age groups were almost the same, suggesting that infection, specially with reovirus type 3, was occurring in all the age groups even beyond 20 years of age.

The authors wish to express their sincerest thanks to Dr Leon Rosen, Pacific Research Section, National Institute of Allergy and Infectious Diseases, Honolulu, Hawaii, for the supply of prototype strains of reoviruses, to Drs B. K. Aikat, Director Professor of Pathology, R. N. Chakravarti, Department of Experimental Medicine, O. N. Bhakoo, and Sucheta Thukral, Department of Paediatrics, Post- Graduate Institute of Medical Education and Research, Chadigarh, for their invaluable help and co-operation, to Prof. P. V. K. Iyer, Department of Mathematics, Panjab University, and to Mr H. D. Gupta, Biostatistician, Post-Graduate Institute of Medical Education and Research, Chadigarh for their statistical analysis of the results.

The authors gratefully acknowledge the helpful criticism and suggestion of Dr C G. Pandit, Ex-Director, Indian Council of Medical Research, during the preparation of the paper.

The authors acknowledge also the technical assistance of Mr Jagmohan Lai Pipat, Mr Gurmeet Singh Khatra, and Mr Amar Singh Saini.

This work was partly supported by the Research Grant of the Indian Council of Medical Research sanctioned to one of the authors (S. R. P.).