Household Contacts Of Index Patients Research Articles

Haemophilus influenzae Type b Colonization in Household Contacts of Infected and Colonized Children Enrolled in Day Care

Strategies for management of children attending day-care facilities after a case of Haemophilus influenzae type b disease are controversial. The success of chemoprophylaxis in preventing subsequent cases has been variable. Failure of rifampin prophylaxis as currently recommended may result from usage limited to direct contacts of the index patient. This prospective study was designed to ascertain the extent of colonization in household contacts of colonized children attending day-care facilities with an index case of H influenzae disease. Outer membrane protein analysis was used to determine similarity between strains isolated from contacts and index patients. Of children attending six day-care facilities, 15% were colonized with subtypes of H influenzae identical with those of their respective index patients, and 7% of children were colonized with different subtypes. Colonization with identical outer membrane protein subtypes in children from day-care homes was more frequent than in the larger day-care centers (91% v 8%, P less than .00001). Within families of children with identical outer membrane protein subtypes, 25% of household members (17% of parents and 44% of siblings) were colonized despite lack of direct contact with the index patients. This colonization rate was comparable to that of household contacts of index patients (26%). Among household contacts of index patients, especially siblings, colonization with H influenzae tended to be lower if the patient attended day care than if the patient did not attend day care (17% v 73%; P = .05 for siblings). We have found that household contacts of colonized day-care children are a reservoir of H influenzae.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiological investigations on Campylobacter jejuni in households with a primary infection.

Fifty-four Rotterdam patients in which a primary infection with Campylobacter jejuni had been detected (index patients) were compared with 54 control subjects with regard to the consumption and preparation of foods 7 days before onset of illness and the keeping of pet animals. Significantly more index patients than controls had eaten chicken meat (47 v. 29; P = 0.0002), particularly at barbecues (14 v. 2; P = 0.0015). Marginally more index patients had eaten pork (47 v. 39; P = 0.048) or inadequately heated meat (13 v. 8), though in the last case numbers were too small to be statistically significant. The consumption of beef or mutton and outdoor eating (other than at barbecues) were essentially the same in both groups. There was no significant association with the keeping of pet animals, although a few more index patients had cage birds than controls (18 v. 12). Twenty-one (15%) of 136 household contacts of index patients also suffered from diarrhoea during the same period. Circumstantial evidence pointed to a common source of infection with the index patient in 13 instances (nine households) and probable intrafamilial spread of infection in six instances. Campylobacters were isolated from one of 110 swabs of kitchen work surfaces and eight of 107 swabs taken from lavatory bowls in index households.

Norwalk gastrointestinal illness: an outbreak associated with swimming in a recreational lake and secondary person-to-person transmission.

An outbreak of gastrointestinal illness in which headache, low grade fever and myalgia were common symptoms occurred among persons who visited a recreational park in Macomb County, Michigan, on July 13-16, 1979. The temporal clustering of onsets of 121 persons who were the first in their households to become ill suggested an incubation period ranging from 4-77 hours. A history of swimming in the park's lake was elicited with significantly greater frequency from these persons than from park visitors who were not ill (age standardized odds ratio = 4.8; 95% confidence interval, 1.8-12.7). One hundred twenty-six park visitors who became ill were household contacts of index patients who had swum in the lake; at least 62 of these 126 cases were probably due to secondary transmission. A secondary attack rate of 19% was observed in household contacts who had not visited the park. Serologic studies identified Norwalk virus as the etiologic agent. The source of the contamination of the lake could not be determined. Although some water samples collected just before and after the epidemic period had high coliform counts, the geometric mean coliform density of all samples collected on those days was within the limits established by the Environmental Protection Agency as acceptable for recreational contact water.