Eradication of dracunculiasis from Pakistan.

In 1986 the World Health Organization targeted dracunculiasis (Guinea-worm disease), which seriously impairs socioeconomic development in 16 African countries, India, Pakistan, and Yemen, to be eradicated globally. The target date for eradication by the end of 1995 was established in 1991. Pakistan eradicated dracunculiasis from the country in October, 1993, after a national campaign which began in 1987 with a nationwide village-by-village search for cases. The infection, which is transmitted by drinking water from ponds containing infected water fleas, was eradicated by using health education, cloth filters, and the cyclopsicide, temephos; and in the later stages, by case containment. Methods pioneered in Pakistan's National Guinea Worm Eradication Program are now being applied in remaining endemic countries.

PIP: Dracunculus medinensis larvae expelled into drinking water may be ingested by water fleas, copepods, in which they undergo two moults before becoming infectious to humans. A person consuming unboiled or unfiltered water infested with larvae-ridden copepods will contract dracunculiasis. The disease is manifest one year later by the emergence from the human host of one-meter-long adult worms of Dracunculus medinensis. Infected people are often incapacitated for several weeks by secondary infections associated with the emergence of the worm, although less than 1% of victims suffer permanent disability. The disease is rarely fatal, but it prevents large numbers of people from farming or attending school. Dracunculiasis, Guinea-worm disease, can be prevented by boiling drinking water or filtering it through a cloth to remove the larvae's copepod hosts, by educating villagers not to contaminate their sources, by providing clean drinking water from underground sources such as borehole wells which cannot be contaminated, or by using a larvicide, temephos, to kill the copepods while leaving the water safe for human consumption. In 1986, the World Health Organization targeted dracunculiasis for global eradication. From an estimated total of more than three million cases in 1986, only 165,000 cases were reported worldwide in 1994. Pakistan, however, is the first country endemic for dracunculiasis to eradicate the disease during the ongoing global campaign. The goal of countrywide eradication was reached in October 1993 after a national campaign which began in 1987 with a nationwide village-by-village search for cases. Health education, cloth filters, temephos, and case containment were used together to achieve success. Methods pioneered in Pakistan's guinea-worm eradication program are being applied in the remaining endemic countries.

Intestinal parasitism in the United States: update on a continuing problem.

To document patterns of intestinal parasitism in the United States, we analyzed results of 216,275 stool specimens examined by the state diagnostic laboratories in 1987; parasites were found in 20.0%. Percentages were highest for protozoans: Giardia lamblia (7.2%), Entamoeba coli and Endolimax nana (4.2% each), Blastocystis hominis (2.6%), and Entamoeba histolytica (0.9%). The most commonly identified helminths were nematodes: hookworm (1.5%), Trichuris trichiura (1.2%), and Ascaris lumbricoides (0.8%). Identifications of G. lamblia increased broadly from the 4.0% average found in 1979, with 40 states reporting increases and seven reporting decreases. Seasonally, Giardia identifications increased in the summer and fall, especially in the Midwest. Nine states reported hookworms in more than 2% of specimens; none were states with indigenous transmission. We analyzed similar, but abbreviated, data for 1991; parasites were found in 19.7% of the 178,786 specimens and Giardia was found in 5.6%. States reporting percentages of Giardia identification in the highest quartile for both 1987 and 1991 were located in the Midwest or in the Northwest. Cryptosporidium was identified in both the 1987 and 1991 surveys; it had not been identified in a previous survey. For each year, Cryptosporidium was reported from 25 states across the country (for both years in 17 states). We conclude that intestinal parasitism should not be overlooked as a cause of gastrointestinal illness in the United States and that the prevalence of Giardia may be increasing.

Results of testing for intestinal parasites by state diagnostic laboratories, United States, 1987.

We analyzed results of 216,275 stool specimens examined by the state diagnostic laboratories in 1987; parasites were found in 20.1%. Percentages were highest for protozoans: Giardia lamblia (7.2%), Entamoeba coli and Endolimax nana (4.2% each), Blastocystis hominis (2.6%), Entamoeba histolytica (0.9%), and Cryptosporidium species (0.2%). Identifications of Giardia lamblia increased broadly from the 4.0% average found in 1979, with 40 states reporting increases and seven decreases. Most states that identified Giardia in more than 9% of specimens were located around the Great Lakes or in the Northwest. Seasonally, Giardia identifications increased in the summer and fall, especially in northern states. The most identified helminths were nematodes: hookworm (1.5%), Trichuris trichiura (1.2%), and Ascaris lumbricoides (0.8%). Other less commonly identified helminths included Clonorchis and Opisthorchis species (0.6%), Strongyloides stercoralis (0.4%), Hymenolepis nana (0.4%), Enterobius vermicularis (0.4%), and Taenia species (0.1%). Tape tests for Enterobius, reported for 35 states, were positive for 11.4% of 9,597 specimens. Nine states (California, Colorado, Hawaii, Idaho, New Jersey, Oregon, Rhode Island, Washington, Wisconsin) reported hookworms in more than 2% of specimens; none were states traditionally associated with indigenous transmission. Cryptosporidium diagnoses, reported by 25 of 49 states, were recorded for the first time in a national survey and showed no marked regional clustering. The Giardia data revealed changes in rates of identification and in geographic patterns compared with state laboratory data collected a decade earlier (1976-1978).

Economical laboratory support system for influenza virus surveillance.

When increases in influenzalike illnesses were first detected during the 1984 to 1985 and 1985 to 1986 influenza seasons, throat swab specimens were mailed by physicians across the United States to one hospital laboratory, and each specimen was inoculated into a single tube of cell culture. Of 165 specimens, 52 (32%) were positive for influenza A or B virus within 3 days of receipt when tested by fluorescence microscopy, permitting positive results to be received by the physicians within 1 week on the average. Approximate direct cost was $16 per specimen.

Lack of significant person-to-person spread of swine influenza-like virus following fatal infection in an immunocompromised child.

In February 1982, a four-year-old Nevada girl with acute lymphoblastic leukemia in remission was hospitalized with fulminant pneumonia and died eight days later at a hospital in California. An influenza virus was the only pathogen detected, and was present in both antemortem and postmortem specimens. The virus was closely related antigenically to A/New Jersey/8/76 (H1N1) and had a genome very similar to a contemporary enzootic swine influenza virus. The patient had had no known contact with swine, and the source of infection could not be determined. Only five possible secondary cases could be detected by retrospective investigation of 62 contacts, and there was no evidence of spread to the general community. Swine influenza viruses circulate among pigs in the United States annually, and it is likely that sporadic transmissions to humans will continue to be detected. Nevertheless, person-to-person spread under these circumstances appears to be limited.

St. Louis encephalitis--Florida 1977. Patterns of a widespread outbreak.

From 8 August through 5 December 1977, 110 laboratory-documented cases (78 confirmed, 32 presumptive) of St. Louis encephalitis (SLE) occurred in 20 counties throughout central-south Florida. Most cases were initially identified through an active surveillance system involving repeated contact of hospital infection control officers. This outbreak had three characteristics that are unusual for SLE epidemics in the eastern United States: it lacked an urban focus, a disproportionate number of cases affected young males, and the epidemic period extended into December. There was no significant difference between attack rates for blacks and whites. Males were significantly more often affected than females. Because of the time required for laboratory confirmation of cases, most outbreak control measures were initiated after the outbreak was declining. Reporting of clinically suspected SLE cases to initiate epidemic mosquito control should improve the timeliness of control measures in future outbreaks.

Reintroduction of dengue fever into the continental United States. I. Dengue surveillance in Texas, 1980.

Two surveillance systems were initiated in Texas in 1980 to detect cases of dengue fever. Physicians throughout the state were requested to report cases of dengue (passive surveillance), and 27 out-patient facilities serving geographically and ethnically high risk populations were asked to report cases of dengue-like illness weekly (active surveillance). Additionally, two clinics participating in active surveillance submitted acute-phase blood specimens weekly for dengue virus isolation. Sixty-three cases of illness due to dengue type 1 infection (dates of onset 2 August-10 November) were documented by virus isolation or serologic testing; 52 of them (83%) occurred n countries adjacent to the Texas-Mexico border. Fifty-six patients (89%) were Hispanic; 46 (73%) were females. Twenty-seven patients (43%) had not traveled outside the U.S. before becoming ill. Since no clinically apparent outbreak of dengue was ever recognized by public health officials in Texas in 1980, the active surveillance system in other Gulf Coast states should be considered when the risk of introduction of dengue is considered high.

An outbreak of Norwalk gastroenteritis associated with swimming in a pool and secondary person-to-person transmission.

In June 1977 an outbreak of acute gastroenteritis affected 103 students and teachers at an elementary school in Ohio. The illness typically lasted 24 hours or less and was characterized by vomiting (86%) and cramping (70%), but more than half of the persons involved also reported having nausea, diarrhea, and headache. Similar illness frequently followed in household members (29%) of families with primary cases. Investigation revealed that 70% of the children and teachers who swam in a pool at an all day outing June 1 (4 classrooms) and 55% of those who swam during a similar outing June 2 (2 classrooms) had the onset of acute illness from 12--48 hours later. None of the children who attended the outings but did not swim had a similar illness. The evidence suggested that the primary outbreak was caused by contaminated water in the pool and that person-to-person spread of illness followed. Results of a microbiologic study of pool water were negative for bacterial and viral pathogens. Throat washings, stool specimens, and paired blood samples studied for evidence of pathogens were negative initially, but subsequent serologic studies suggested that infection by Norwalk virus was the cause of the outbreak. The pool chlorinator which was inadvertently unconnected at the time of the school visits was reconnected and an underground leak in the water supply pipes was corrected. No more cases were reported after the pool was drained, cleaned, and reopened.

La Crosse virus infection and disease in western North Carolina.

Active surveillance for La Crosse infection from 1977 to 1979 revealed 12 laboratory documented cases in children from the Cherokee reservation and nearby areas of western North Carolina. The annual rate of hospitalization with La Crosse virus was isolated from two of 34 pools of male and one of 34 pools of female Aedes triseriatus mosquitoes reared from larvae collected around the residences of reservation children who had been hospitalized with encephalitis. The occurrence of the recent cases, the history of cases in 1964 and 1965, and the demonstration of antibodies to La Crosse virus in sera from second grade children collected in 1968 (2%), in 1978 (4.5%), and in high school students in 1979 (11.3%), indicate that La Crosse has persisted in the Cherokee area for at least 15 years. La Crosse infection is infrequently reported from the southeast, but this may reflect inactive surveillance. More frequent testing would reveal whether La Crosse is a significant health problem in other areas of the southeast.

Dengue in the Seychelles.

Epidemics of dengue-like illness occurred in the Seychelles from December 1976 to April 1977 and from December 1978 to January 1979. Dengue 2 virus was isolated from individuals who had been in the Seychelles in 1977. From February to April 1979, sera were collected from outpatients in Mahé, Seychelles, who had not previously been hospitalized with a dengue-like illness. Results of neutralization tests with these sera indicated that prevalence rates for the four dengue viruses were between 81% and 91.8% and that dengue 2 was the most probable etiological agent in the epidemics. In addition, antibodies to chikungunya (8.7%) and Sindbis (7.4%) viruses were found, providing, for the first time, evidence of the presence of these two alphaviruses in the Seychelles.