Active surveillance and risk factors for leptospirosis in Hawaii.

A clinic-hospital-based leptospirosis surveillance program was conducted to determine the morbidity and risk factors in nonepidemic settings. The study was conducted on two islands, Kauai and Hawaii (Big Island), in the state of Hawaii for one year during 1988 and 1989. An active, more comprehensive case detection system was used on the Big Island that enabled us to determine the incidence of clinical disease. Subjects from both islands were used to conduct a case-control study for risk factors. One hundred seventy-two subjects from the Big Island (who presented with any two of the following symptoms: fever, headache, myalgia, or nausea/vomiting) were enrolled in the study. Twenty cases were diagnosed by culture, serology, or fluorescent antibody tissue staining at autopsy. Six cases required hospitalization and two succumbed to fatal infections. We estimated that these cases represented an annual incidence rate of 128 per 100,000 person-years in our target population. For 33 cases, 77 controls were matched for island, age, sex, and time of onset of illness. Interviews were conducted retrospectively in a double-blinded fashion with cases and controls and evaluated approximately 30 risk factors. Factors that were associated most strongly with development of leptospirosis were household use of rainwater catchment systems (P = 0.003), presence of skin cuts during the incubation period (P = 0.008), contact with cattle or the urine of cattle (P = 0.05 and P = 0.03, respectively), and handling of animal tissues (P = 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Salmonella egg survey in Hawaii: evidence for routine bacterial surveillance.

One hundred and six dozen eggs, representing 12 brands, were purchased from Oahu supermarkets and cultured for Salmonella using standard FDA (Food and Drug Administration) microbiological techniques. Two enrichment incubation temperatures were used to improve culture sensitivity. Ten cartons (9.4 percent) of the 106 dozen samples had shells positive for Salmonella. Seven of the 10 were traced to a single egg processor. Inspection of the facility led to the discovery of malfunctioning equipment used in the egg washing and sanitation process.

Salmonellosis in the marine environment. A review and commentary.

Marine cetaceans (whales and dolphins), pinnipeds (seals and sea lions), reptiles (turtles and crocodyles), fish and shellfish, and fish-eating birds have been found to harbor salmonellae. In some of these animals, clinical salmonellosis has been demonstrated, but in many cases, the isolated salmonellae may have been an opportunistic pathogen with the illness or death of the host due to other causes. On the basis of the few reports in the literature, marine reptiles (turtles and crocodyles), fish, and shellfish appear to be passive carriers of salmonellae and demonstrate no clinical disease. All of these animals constitute a potential source of salmonellosis in man and his domestic animals. The role of wild and domestic terrestrial animals and fresh water aquatic animals in the transmission of salmonellosis to man has been recognized for many years. The situation with regard to the marine (saltwater) animals has never been adequately investigated or reported. In the past, much reliance has been placed on the ability of saline waters to inhibit or destroy human pathogens, including the salmonellae. Whether this effect is chemical, physical or biological has been studied since the late nineteenth century, and the investigators have found a number of factors affecting both the inhibition and stimulation of growth of salmonellae in saline waters. Salmonellae have been isolated from or found to survive in seawater with salinities as high as 3.5 percent. Marine animals in many parts of the world have been found harboring salmonellae.

Leptospirosis in Hawaii: shifting trends in exposure, 1907-1984.

Leptospirosis was first recognized as an occupational disease of sugar plantation workers in Hawaii in 1907. Since then, shifts have been noted in the animal transmission cycles, the occupational groups at risk, and an increasing recognition of cases associated with avocational exposure. Surveys of the small mammal populations indicate rats, mice, and mongooses are the most important vectors in Hawaii. Serologic surveys of workers in high-risk occupations show antibody prevalence rates ranging from 12 to 82 percent. The epidemiology of leptospirosis in Hawaii is described, based on 182 cases reported to the Hawaii Department of Health from 1970-1984. The most common infecting serovar was mankarso in the Icterohaemorrhagiae serogroup; other serovars in the Icterohaemorrhagiae group were also frequently implicated as causing disease. The manifestations of disease noted by physicians in Hawaii are similar to those observed in the continental U.S. Fever, myalgia, and headache were the most common symptoms reported in the majority of cases in Hawaii; jaundice was noted in the records of 24 percent. Recommendations made to interrupt the cycle of transmission and reduce the chances of exposure in occupational settings include the control of rodent populations and vaccination of domestic animals. Personal hygiene among workers is to be encouraged, and the development of prophylactic measures is suggested either by immunization or by chemoprophylaxis.

Epidemiologic aspects of salmonellosis in reptiles, amphibians, mollusks and crustaceans--a review.

Salmonellae have been found associated with all of the poikilothermic vertebrate species studied, as well as the mollusks and crustaceans. Some of these animals have been incriminated in the transmission of salmonellosis to other higher vertebrates or to man, but in many cases they remain as only potential sources of the disease because of inadequate epidemiologic study. It would appear that they are important unrecognized reservoirs of the Salmonella organism in nature. With the increasing worldwise emphasis on aquaculture as a source of food, the role these animals play in the maintenance or transmission of salmonellosis in the aquatic environment needs further study. The epidemiologic investigation of sporadic outbreaks of salmonellosis might well take into consideration some of the common household and backyard pests--flies, ants, cockroaches, lizards (geckos), toads, and snails.

Leptospirosis in poikilothermic vertebrates. A review.

Autochthanous leptospirosis does occur in the poikilothermic vertebrates, as evidenced by positive serological reactions and by the isolation of pathogenic leptospiral serovars. These findings in aquatic members of this group are of special importance in view of the increased worldwide interest in aquaculture farming. Since 1975, 24 of the 101 (23.7%) reported human cases of leptospirosis in Hawaii have been associated with aquaculture industries (taro farms, prawn farms and watercress farms). Antibody synthesis and persistence in these animals is variable, and seems to depend to some extent on environmental temperatures. Some members of the group apparently lack the capacity for immunological memory, experience a considerable delay (lag-phase) in antibody formation, demonstrate the "paradoxical reaction" found in other animals, and can maintain living pathogenic leptospirae in their organs in the absence of detectable antibody utilizing our present serologic methods. For these reasons, serological studies as the sole source of evidence for leptospiral infection cannot be recommended. The immunologic mechanism of lower vertebrates is not known, some studies suggesting that there may be more than one antibody system active in these animals, especially the turtles, and further investigation at the cellular and subcellular levels is indicated. The growth temperatures and nutritional requirements of leptospirae isolated from other than warm-blooded animals is also poorly understood. Some knowledge has been contributed by various investigators in recent years, but much more work needs to be done in studying the nutritional and metabolic requirements of leptospirae isolated from all sources, including the various fauna resident in and around the fresh water streams and ponds.