Allen W. Hightower

The bacterium Listeria monocytogenes is a motile, gram-positive coccobacillus that can frequently be isolated from soil, water, and vegetation. It is a common cause of meningoencephalitis and abortion in ruminants, but it is infrequently identified as a human pathogen. In adults, L. monocytogenes is an uncommon cause of bacterial meningitis and a rare cause of sepsis, endocarditis, peritonitis, or focal abscess. In neonates, it is the third most common cause of bacterial meningitis after Escherichia coli and Streptococcus agalactiae. In addition, perinatal infections can cause abortion, stillbirth, and a devastating septic illness termed "granulomatosis infantisepticum."The mode of acquisition . . .

Spatial analyses of the effect of insecticide (permethrin)-treated bed nets (ITNs) on nearby households both with and without ITNs was performed in the context of a large-scale, group-randomized, controlled mortality trial in Asembo, western Kenya. Results illustrate a protective effect of ITNs on compounds lacking ITNs located within 300 meters of compounds with ITNs for child mortality, moderate anemia, high-density parasitemia, and hemoglobin levels. This community effect on nearby compounds without nets is approximately as strong as the effect observed within villages with ITNs. This implies that in areas with intense malaria transmission with high ITN coverage, the primary effect of insecticide-treated nets is via area-wide effects on the mosquito population and not, as commonly supposed, by simple imposition of a physical barrier protecting individuals from biting. The strength of the community effect depended upon the proportion of nearby compounds with treated nets. To maximize their public health impact, high coverage with treated nets is essential.

A prospective, laboratory-based surveillance project obtained accurate data on meningitis in a population of 34 million people during 1986. Haemophilus influenzae was the most common cause of bacterial meningitis (45%), followed by Streptococcus pneumoniae (18%), and Neisseria meningitidis (14%). Rates of H. influenzae meningitis varied significantly by region, from 1.9/100,000 in New Jersey to 4.0/100,000 in Washington state. The overall case fatality rates for meningitis were lower than those reported in several studies from the early 1970s, suggesting that improvements in early detection and antibiotic treatment may have occurred since that time. Concurrent surveillance was also performed for all invasive disease due to the five most common causes of bacterial meningitis. Serotypes of group B streptococcus other than type III caused more than half of neonatal group B streptococcal disease and mortality, suggesting that an optimal vaccine preparation must be multivalent. Of the organisms evaluated, group B streptococcus was the second most common cause of invasive disease in persons greater than 5 years old.

Lyme disease is a tick-borne illness that has been reported from three regions in the United States--the Northeast, Midwest, and West--which correspond to the distribution of the recognized vectors of the disease, Ixodes dammini and Ixodes pacificus. In 1982, a surveillance system designed to define the morbidity and geographic distribution for Lyme disease by using a clinical case definition received information on 491 definite cases and 38 probable cases. Of the definite cases, 489 were acquired in endemic areas of the Northeast or Midwest; one case was acquired in Utah and one in western Pennsylvania, two areas where the illness had not been previously reported. Three states that previously had not reported cases of Lyme disease (Kentucky, Indiana, Montana) reported probable cases. In 37% of the definite cases, the patients had neurological symptoms (most commonly reported was headache with stiff neck, suggestive of meningitis), 10% cardiac symptoms (most commonly reported was palpitations), and 54% arthritic symptoms (most commonly reported in large joints). The occurrence of Lyme disease in areas outside the currently recognized endemic regions, as well as the recent description of Amblyomma americanum as a probable vector, suggest that additional vectors may be described in the future.

Diarrhea occurs frequently among persons with the acquired immunodeficiency syndrome, but the cause often remains unknown. We used a group of diagnostic assays to determine which viruses were etiologic agents of diarrhea in a group of persons infected with the human immunodeficiency virus (HIV).