Screening for tuberculosis infection among secondary school students in Minneapolis-St. Paul: policy implications.

Three students in the St. Paul Public Schools were diagnosed with active tuberculosis (TB) in late 1991 and early 1992. To define the prevalence of TB infection in St. Paul and Minneapolis, we conducted school-based screening projects in the St. Paul and Minneapolis public schools during 1992 and 1993. In St. Paul, 7,596 (74.8%) students in grades six through 12 received Mantoux tests; 268 (3.5%) were reactive. Infection rates varied significantly by country of birth, with students born outside the United States more likely to be Mantoux reactors than U.S.-born students (RR = 20.2; 95% CI = 14.9-27.3; p < 0.001). In Minneapolis, 752 (47.2%) eighth-grade students received Mantoux tests; 23 (3.1%) were reactive. As in St. Paul, infection rates varied by country of birth; students born outside the United States were more likely to have reactive Mantoux tests than students born in this country (RR = 13.2; 95% CI = 5.6-31.4; p < 0.001). We conclude that routine TB screening of school students is not warranted in Minnesota, although school-based screening targeted at the highest risk students, particularly those born outside the United States, may be a beneficial prevention strategy.

Measles. Forgotten but not gone.

Vaccination has greatly reduced the incidence of measles in the United States. Yet, because of the highly infectious nature and potentially fatal complications of the disease, primary care physicians need to remain alert to possible cases and to react aggressively during an outbreak. Dr Holtan discusses why measles persists, who is at risk, and how immunity is achieved.

Giardiasis. A crimp in the life-style of campers, travelers, and others.

Once Giardia cysts leave the host, they die quickly if dehydrated but can survive for two months in water as cold as 8 degrees C (46 degrees F). Thus, giardiasis is transmitted through ingestion of infected feces or water. Infection most often causes diarrhea, but if a subacute or chronic form develops, additional signs and symptoms of intestinal distress may be present. Diagnosis is made by finding cysts in a stool sample and/or trophozoites in duodenal fluid. In rare cases, small-bowel biopsy may be necessary. Whether to treat asymptomatic giardiasis is debatable. Drug treatment spares the patient unpleasant symptoms that may develop and eliminates transmission, but available drugs can have side effects and none has been proven safe for pregnant women. By far, the best approach to giardiasis is prevention through education of travelers, nature lovers, and workers in day-care centers and institutions that house the incontinent.

Helminthiasis. Tips for getting rid of unwelcome guests.

Helminthic parasites usually cause uncomplicated infections of the intestine. Complications can arise from nutritional competition between parasite and host, mechanical obstruction of the intestine or common bile duct (in ascariasis), and an overwhelming, fatal infection among immunocompromised hosts (in strongyloidiasis). Diagnosis is made by testing stool samples, except for Enterobius, which can often be seen in the perianal area. Treatment in uncomplicated cases is straightforward and easy. Several drugs are available, and the regimen depends on which parasites are present. However, none is safe for use in pregnant women.

Splenomegaly in Hmong refugees.

We review asymptomatic splenomegaly in Indochinese refugees and provide recommendations for evaluation of the problem. Prevalence of splenomegaly in newly arrived Indochinese refugees was 2.5%, three times more prevalent in the Hmong than in the non-Hmong refugees. Male Hmong refugees aged 15 to 29 years had the highest prevalence (10%). For the 50 Hmong refugees studied, there was no evidence that their splenomegaly was caused by clonorchiasis, schistosomiasis, tuberculosis, syphillis, lymphoma, tropical splenomegaly syndrome, or clinical malaria. Cases were more likely to have hepatomegaly, hepatitis B surface antigen positivity, and a low mean corpuscular volume than a reference population of Hmong refugees. Malaria antibody titers were elevated in all but one of the 41 cases (98%) tested.