The potential effect of global warming on the geographic and seasonal distribution of Phlebotomus papatasi in southwest Asia.

The distribution of Phlebotomus papatasi in Southwest Asia is thought to be highly dependent on temperature and relative humidity. A discriminant analysis model based on weather data and reported vector surveys was developed to predict the seasonal and geographic distribution of P. papatasi in this region. To simulate global warming, temperature values for 115 weather stations were increased by 1 degree C, 3 degrees C, and 5 degrees C, and the outcome variable coded as unknown in the model. Probability of occurrence values were then predicted for each location with a weather station. Stations with positive probability of occurrence values for May, June, July, and August were considered locations where two or more life cycles of P. papatasi could occur and which could support endemic transmission of leishmaniasis and sandfly fever. Among 115 weather stations, 71 (62%) would be considered endemic with current temperature conditions; 14 (12%) additional stations could become endemic with an increase of 1 degree C; 17 (15%) more with a 3 degrees C increase; and 12 (10%) more (all but one station) with a 5 degrees C increase. In addition to increased geographic distribution, seasonality of disease transmission could be extended throughout 12 months of the year in 7 (6%) locations with at least a 3 degrees C rise in temperature and in 29 (25%) locations with a 5 degrees C rise.

Use of weather data and remote sensing to predict the geographic and seasonal distribution of Phlebotomus papatasi in southwest Asia.

Sandfly fever and leishmaniasis were major causes of infectious disease morbidity among military personnel deployed to the Middle East during World War II. Recently, leishmaniasis has been reported in the United Nations Multinational Forces and Observers in the Sinai. Despite these indications of endemicity, no cases of sandfly fever and only 31 cases of leishmaniasis have been identified among U.S. veterans of the Persian Gulf War. The distribution in the Persian Gulf of the vector, Phlebotomus papatasi, is thought to be highly dependent on environmental conditions, especially temperature and relative humidity. A computer model was developed using the occurrence of P. papatasi as the dependent variable and weather data as the independent variables. The results of this model indicated that the greatest sand fly activity and thus the highest risk of sandfly fever and leishmania infections occurred during the spring/summer months before U.S. troops were deployed to the Persian Gulf. Because the weather model produced probability of occurrence information for locations of the weather stations only, normalized difference vegetation index (NDVI) levels from remotely sensed Advanced Very High Resolution Radiometer satellites were determined for each weather station. From the results of the frequency of NDVI levels by probability of occurrence, the range of NDVI levels for presence of the vector was determined. The computer then identified all pixels within the NDVI range indicated and produced a computer-generated map of the probable distribution of P. papatasi. The resulting map expanded the analysis to areas where there were no weather stations and from which no information was reported in the literature, identifying these areas as having either a high or low probability of vector occurrence.

Pneumonia hospitalizations in the US Navy and Marine Corps: rates and risk factors for 6,522 admissions, 1981-1991.

The authors identified hospitalizations for pneumonia (n = 6,522) in active-duty Navy and Marine Corps personnel during 1981-1991 from computerized inpatient records. The crude mean annual rate of pneumonia hospitalization was 77.6 per 100,000 active-duty personnel; 65% of pneumonia hospitalizations had no etiologic agent identified. The most commonly reported agents to cause pneumonia hospitalization were Streptococcus pneumoniae (12.3%), Mycoplasma pneumoniae (10.8%), other streptococcal species (2.1%), and Haemophilus influenzae (1.9%). The median age at hospitalization was 22 years. The median duration of hospital stay was 4 days and the case fatality rate was 0.4%. The authors used a 2% sample of the entire population and by means of stepwise unconditional multivariate logistic regression modeling for pneumonia found that, independent of age, the most junior Navy and Marine Corps personnel were at highest risk. Whites were at higher risk than blacks, Hispanics, or Filipinos. These results indicate that among this generally healthy US young adult military population, pneumonia hospitalization is common, often brief, and frequently without specifically identified pathogens.

Tuberculosis infection among young adults entering the US Navy in 1990.

BACKGROUND: From 1958 through 1969, more than 1.2 million US Navy recruits received tuberculin skin tests; 5.2 per 100 were tuberculin reactors. Subsequent analyses predicted a downward trend in the risk of tuberculosis infection in the United States. We sought to determine the current prevalence of tuberculin reactors by sex, race/ethnic group, and birthplace among young adult residents of the United States entering the US Navy. METHODS: Recruits routinely receive a tuberculin skin test on entering US Navy recruit training in Great Lakes, Ill, Orlando, Fla, or San Diego, Calif. In January and February 1990, 2416 young men and women (mean age, 20.6 years) received tuberculin skin tests and completed questionnaires eliciting demographic and tuberculosis risk factor data. A tuberculin reactor was defined as a subject having 10 mm or greater induration to a skin test with 5 tuberculin units, purified protein derivative, administered intradermally by the Mantoux method. RESULTS: Fifty-five of 2214 men (2.5 per 100; 95% confidence interval, 1.9 to 3.2 per 100) and five of 202 women (2.5 per 100; 95% confidence interval, 0.8 to 5.8 per 100) were tuberculin reactors. For men, the prevalence was greater in blacks (5.2 per 100), Hispanics (5.4 per 100), and Asian/Pacific Islanders (26.4 per 100) than in whites (0.8 per 100) and greater in foreign-born recruits (19.2 per 100) than in recruits born in the United States (1.6 per 100). Women had the same pattern of prevalence by race/ethnic group and birthplace. CONCLUSIONS: The prevalence of tuberculosis reactors declined as predicted among young adults, especially the white US-born recruits, entering the US Navy. Although the prevalence also declined among nonwhites and the foreign-born recruits, a substantial proportion continue to enter adulthood with preexisting tuberculosis infection.

Upper respiratory disease in deployed U.S. Navy shipboard personnel.

A study was conducted to determine the risk of upper respiratory disease among deployed U.S. Navy shipboard personnel. Between January and June 1989, a Patient Encounter Form was used to collect disease information from 10 U.S. Navy ships. Patients with a diagnosis of upper respiratory infection (URI) on initial sick-call visit were used in this study. Information on time spent in various ports and time at sea for each of the 10 ships was also collected. A classification scheme was developed to permit daily estimates of URI rates and to indicate whether the ship was in port or at sea. Of 967 cases of URI, 64.4% occurred while at sea, with an average daily rate of 0.5/1,000 crew members; 35.4% of the cases occurred while in port, with an average daily rate of 0.4/1,000 crew members. There was an increase in URI rates after 9 days at sea or in port. These data suggest that there are defined periods of increased transmission of upper respiratory infections aboard ships, both at sea and in port.

Geographic risk factors for viral hepatitis and cytomegalovirus infection among United States Armed Forces blood donors.

In an effort to determine whether residence in a foreign country increases the risk of hepatitis B and C and cytomegalovirus (CMV) infection in United States (US) Armed Forces blood donors, 5719 volunteer donors at four US Navy blood banks were evaluated. Most participants were repeat donors (68%) and were young (mean age, 25 years), male (88%), and white (80%), black (10%), or Hispanic (7%). Birth outside of the United States was reported by 6 percent of subjects, and 34 percent had lived in a foreign country for more than 3 months. Twenty (0.3%) subjects had hepatitis B surface antigen (HBsAg), and 100 (1.7%) had antibody to hepatitis B core antigen (anti-HBc). Thirty-four (0.6%) were repeatably reactive in enzyme-linked immunosorbent assay for antibody to hepatitis C virus (anti-HCV); 11 (0.2%) had anti-HCV in immumoblot assay. Of the 3484 donors tested for anti-CMV, 1117 (32.1%) were positive. When demographic characteristics were controlled for both anti-HBc and anti-CMV seropositivies were independently associated in male blood donors with residence in the Philippines. Geographic factors were not associated with HBsAg and anti-HCV positivity. These findings indicate that the prevalence of serologic markers for viral hepatitis is low in military blood donors, but that residence in the Western Pacific is a risk factor for hepatitis B and CMV infection.

Tuberculin skin testing in US Navy and Marine Corps personnel and recruits, 1980-86.

An extensive skin testing program is part of the United States Naval Medical Command's infectious disease control effort. From 1980 to 1986, 2,306,533 skin tests, using five TU PPD, were performed on active-duty Navy and Marine Corps personnel, 0.97 percent of which were positive. A downward trend in positive tests was found with a high of 1.43 percent in 1980 and a low of 0.80 percent in 1983. Since 1984, the percentage of positive tests has remained the same or increased. Shore-based medical facilities around the world reported 1,491,646 skin tests with 1.07 percent positive; Navy ships reported 814,887 skin tests with 0.78 percent positive. PPD-positivity for ships in the Pacific area was higher (0.98 percent) than for ships in the Atlantic (0.62 percent). During this same period, the percentage of positive tests in Navy and Marine Corps recruits ranged from a high of 1.82 percent in 1981 to a low of 1.23 percent in 1986. Since 1984, the percentage of positive tests has remained relatively stable in recruits. The frequency of positive PPD tests found in this study is lower than the percentage positive (1.59 percent) found in active-duty Navy personnel in 1969 and the percentage positive (5.2 percent) found in a study of Navy and Marine Corps recruits between 1958 and 1969.