Pertussis epidemic in Oklahoma. Difficulties in preventing transmission.

From Jan 1 to Dec 31, 1983, 351 cases of pertussis were reported in Oklahoma. Overall, 59% of the cases were among children 3 months to 6 years of age, the target age group for pertussis vaccination; only 42% of the patients in this age group were appropriately immunized for age with diphtheria and tetanus toxoids and pertussis vaccine (DTP). A survey of 185 households in the neighborhoods of three cases found that only 65% of 57 children 3 months to 6 years of age were appropriately immunized for their age. Aggressive control of the outbreak was attempted in Oklahoma County with recommendations for widespread vaccination against pertussis. However, the effort failed to immunize 82% of the 931 children in the initial target group. Nonetheless, analysis of the reported cases suggested that less than one fourth of the cases were potentially preventable by a single additional dose of DTP, ie, in individuals 3 months to 6 years of age with a history of at least one prior dose of DTP who were not appropriately immunized for age. The optimal solution to outbreak control is outbreak prevention by ensuring that the maximal number of children younger than 7 years of age receive routine age-appropriate DTP vaccination.

The method of transmission of epidemic influenza: further evidence from archival mortality data.

Evidence for influenza-associated excess mortality in the three centuries before the 20th has been sought from parish burial registers in Cumbria, Devon, Dyfed, East Anglia, Gloucestershire and Northumbria, compared with inter-epidemic years. Most of the registers showed excess of burials concordant with eight historic influenza epidemics. Comparison of the dates of these epidemics, deduced from the burials data in different areas, showed a rate of spread difficult to reconcile with direct person-to-person spread of influenza from the sick. An alternative explanation based on development of latency of the virus in the sick person and subsequent seasonal reactivation is discussed.

Epidemic measles in Chicago in 1983. Sustained transmission in the preschool population.

We evaluated epidemiologic features of 54 patients with measles seen at Wyler Children's Hospital during a 1983 measles epidemic in Chicago. Forty-one (76%) were less than 5 years old, and 23 (43%) were less than 16 months old. We found evidence of a low rate of measles immunity in preschool-aged children of immunization age immediately before the epidemic; only 62% of 173 emergency room patients this age had antibody on enzyme-linked immunosorbent assay. These observations, together with failure of school-based control measures to significantly affect the observed course of the epidemic, indicate that the preschool population sustained the epidemic. Unimmunized preschool-aged children are important in the current epidemiology of measles, and improved immunization strategies are needed to control measles in this population in Chicago and perhaps other cities.

Diarrhea associated with adherent enteropathogenic Escherichia coli in an infant and toddler center, Seattle, Washington.

During November 1983, the Seattle-King County Department of Public Health investigated an outbreak of diarrhea associated with enteropathogenic Escherichia coli, serogroup 0111:K58, in an infant and toddler day-care center. Of the 25 children in the center, ranging in age from 4 to 30 months (median age 11 months), diarrhea occurred in 14 characterized by watery, greenish stools. The median duration of diarrhea was 12 days. Two of the ill children were hospitalized because of severe dehydration. Stool cultures from the children diagnosed initially did not yield the common bacterial pathogens, parasites, or rotavirus. Stool cultures from 11 of 14 ill children and two of 11 well children (P less than .005), however, yielded an E coli serogroup, 0111:K58, which was not invasive or toxigenic by standard tests. The source of the organism was not identified. Although this organism has been recognized as a cause of diarrhea in newborn nurseries, this is the first published report of a documented outbreak of enteropathogenic E coli-induced diarrhea in a day-care center in the United States.

Human viruses in sediments, sludges, and soils.

Recent studies have provided a greater understanding of the movement of viruses in the environment by their attachment to solids. These studies have focused on solids-associated viruses present in wastewater discharged into the ocean and on viruses in sludge and wastewater that may be retained in soil following their land disposal. Such ocean or land disposal of wastewater and sludge may result in a discharge of one or more of 120 human enteric virus pathogens including those causing poliomyelitis, viral hepatitis A and acute gastroenteritis.Solids-associated viruses in effluents discharged into coastal waters accumulate in bottom sediments, which may contain 10 to 10 000 more virus per unit volume than the overlying seawater. Solids-associated viruses resuspended by water turbulence may be transported from polluted to distant non-polluted recreational or shellfish-growing water. Transmission of viruses causing hepatitis or gastroenteritis may result from contact by bathers or swimmers with these viruses in recreational waters, or from ingestion of raw or improperly cooked shellfish in which the solids-associated virus had been bioaccumulated.The land disposal of sludge and wastewater has a potential of causing infections in farm workers, contamination of crops, pollution of raw potable water sources or infiltration of ground water. Viruses retained on soils can be released by rain water and may contaminate ground water through lateral and vertical movements.

An unexplained illness in West Otago.

An apparent epidemic of undiagnosed illness in a rural general practice was investigated. The aims were to describe the illness, the characteristics of the people affected, and to look for possible causes. The patients were questioned about their symptoms, and both patients and controls matched for age and sex, were questioned about possible aetiological factors. Twenty-eight cases were identified; all but three were less than 45 years of age; there were equal numbers of females and males. The most commonly experienced symptoms were tiredness, mood and sleep disturbances, headache, and joint or muscle pains. Results of the case-control study suggested that pollution of the water supply, zoonotic infections, contact with agricultural chemicals, and self-dosing with selenium were unlikely to be causes of this illness. An unidentified virus was regarded as the most likely cause.

A large outbreak of hepatitis A in a day-care center: association with non-toilet-trained children and persistence of IgM antibody to hepatitis A virus.

In early summer, 1979, a large outbreak of hepatitis A occurred in an Oklahoma day-care center. A total of 41 cases were confirmed, all in adults. Of the 115 non-employee households represented by children in the center, 19 households (16.5%) had one or more cases of hepatitis. Hepatitis occurred in 29% of the households with at least one non-toilet-trained child, compared to 2% of the households without such a child (p = 0.00004). At least four (15%) of 27 center employees had hepatitis. Of 26 cases tested serologically, all were positive for hepatitis A antibody (anti-HAV), and 24 of these 26 were also positive for anti-HAV of immunoglobulin class M (anti-HAV IgM), at an average time after onset of illness of 80 days (range, 38-142 days). Three of ten persons remained anti-HAV IgM-positive 164 days after onset.

Viral hepatitis: a four-year hospital and general-practice study in Sydney. 2. Transmission of viral hepatitis among residential contacts in Sydney.

Clinical and serological study of household contacts of index patients suffering from acute viral hepatitis showed the high infectivity of hepatitis A viral (HAV) for susceptible contacts. The anti-HAV specific IgM developed in sera of 67% of susceptible children and 31% of susceptible adult contacts. Of 81 susceptible contacts whose sera became anti-HAV positive, 28.4% developed clinically overt hepatitis. Administration of human immunoglobulin reduced the rate of clinical expression of hepatitis A among susceptible contacts; it also appeared to reduce the actual infection rate. The infection rate among susceptible adult contacts of adult index cases suffering from hepatitis B was 24%. Of 25 susceptible contacts whose sera became HBV-marker positive, 24% developed clinical illness. Transmission occurred probably both by parenteral and non-parenteral means. It is currently not possible to determine susceptibility or seroconversion to hepatitis non-A non-B agents.

Methicillin-resistant Staphylococcus aureus. Epidemiologic observations during a community-acquired outbreak.

Infection with strains of methicillin-resistant Staphylococcus aureus occurred in 40 patients at time of admission to a large urban hospital from March to December 1980. Community-acquired methicillin-resistant S. aureus infections occurred in 24 drug abusers and 16 nonabusers. Patients with infections had a longer mean hospitalization and previously had received antimicrobial therapy more frequently than control subjects. Drug abusers with infections had been treated with cephalosporins more often than control subjects (P less than 0.05). Phage typing of 32 isolates showed that 21 were linked by a common phage type (29/52/80/95). Transmission of methicillin-resistant S. aureus from community-acquired cases occurred in the hospital. By January 1981, methicillin-resistant S. aureus accounted for 30.6% of nosocomial S. aureus infections at Henry Ford Hospital. Methicillin-resistant S. aureus infection may arise in the community as well as in the hospital and has the potential to disseminate in both settings.