Biomedical subjects
Publications and source records attributed to Eli Schwartz.
An ongoing measles outbreak in Israel, involving ≈3,200 cases and 16 deaths, threatens the country's measles elimination status and reflects declining vaccination rates observed globally and within Israel. Epidemiologic investigations supported by sequencing suggest that a single importation triggered the outbreak, underscoring the critical role of rapid genomic surveillance in outbreak control.
BACKGROUND: Most antimalarial agents used by travelers act on the parasite's blood stage and therefore do not prevent late-onset illness, particularly that due to species that cause relapsing malaria. We examined the magnitude of this problem among Israeli and American travelers. METHODS: We examined malaria surveillance data from Israel and the United States to determine the traveler's destination, the infecting species, the type of chemoprophylaxis used, and the incubation period. RESULTS: In Israel, from 1994 through 1999, there were 300 cases of malaria among returning travelers in which one species of plasmodium could be identified. In 134 of these cases (44.7 percent), the illness developed more than two months after the traveler's return; nearly all of these cases were due to infection with Plasmodium vivax or P. ovale. In 108 of the 134 cases (80.6 percent), the patient had used an antimalarial regimen according to national guidelines. In the United States, from 1992 through 1998, there were 2822 cases of malaria among travelers in which the cause could be evaluated. Late illness developed in 987 (35.0 percent) of these travelers. The infection was due to P. vivax in 811 travelers, P. ovale in 66, P. falciparum in 59, and P. malariae in 51; 614 (62.2 percent) of those with late-onset illness had appropriately taken an effective antimalarial agent. CONCLUSIONS: In more than one third of malaria-infected travelers, the illness developed more than two months after their return. Most of these late-onset illnesses are not prevented by the commonly used and effective blood schizonticides. Agents that act on the liver phase of malaria parasites are needed for more effective prevention of malaria in travelers.
We report a case of atovaquone-proguanil-resistant Plasmodium falciparum malaria acquired by a nonimmune traveler to Kenya. Recurrent parasitemia occurred 30 days after directly observed therapy with a combination of atovaquone and proguanil. Treatment failure was confirmed by genetic fingerprinting and sequencing. The primary isolate had wild-type sequence of cytochrome b; however, the recrudescent isolate had a single mutation at position 268 (Tyr268Ser).
Dermatobia hominis is the most common cause of myiasis in Central and South America, affecting mammals and humans, causing nonhealing furuncle-like lesions. During the years 1994 to 1999, 14 Israeli travelers returning from South America were diagnosed with D hominis myiasis. The approach consists of correct diagnosis and a proper removal of the larvae, after which the patients heal with no complications.
In recent years, New World cutaneous leishmaniasis has been seen at a higher incidence among returning Israeli travelers. Leishmania braziliensis and related species cause unsightly cutaneous lesions possibly complicated with a mucosal disease. A total of 12 patients with New World cutaneous leishmaniasis were treated in our clinic, 11 of whom (92%) acquired the disease in the Bolivian Amazon Basin. Five (42%) had regional lymphadenopathy in addition to cutaneous lesions. Polymerase chain reaction was performed for 8 patients to identify the causative Leishmania species. In all, 9 patients (75%) were cured by a single course, and 3 (25%) after an additional course of intravenous sodium stibogluconate. The treatment was well tolerated clinically. Laboratory abnormalities, mainly elevation of liver enzymes (58%), were reversible. We concluded that polymerase chain reaction is a useful tool in establishing the species diagnosis of leishmaniasis and that sodium stibogluconate appears to be a safe and effective treatment for L braziliensis infection.
Hematospermia associated with schistosomal infection is a new topic of clinical interest. The features and incidence of this rare complication and the difficulties associated with its treatment have yet to be characterized. We describe 4 patients with hematospermia due to schistosome infection acquired during travel to an area of endemicity.
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Schistosoma infection is one of the most common infectious diseases, limited in the past only to the endemic countries. With the enormous increase in migration and travel, we encounter more and more cases in developed, nonendemic countries. Although the disease has been known for many years from studies in the endemic countries, the new patient population of nonimmune travelers presents with a different clinical pattern that requires further investigation. One of the features of the disease in the nonendemic population is pulmonary involvement that seems to be much more common than previously suspected. The differences between the nonimmune population with the early pulmonary involvement and the population of endemic areas with late pulmonary involvement are summarized in Table 1. Clinicians in the Western countries have a higher chance of encountering the early (acute) form of the disease, although immigrants from endemic countries may present with late (chronic) schistosomiasis. In the differential diagnosis of pulmonary pathology, especially when accompanied by eosinophilia, schistosomal infection should be considered. The travel history of the patient is mandatory for an evaluation.
Malaria was eradicated in Israel about 50 years ago. Despite this, the number of cases of malaria in Israel has been increasing in the past few years due to imported malaria from endemic countries. Although malaria is a preventable and treatable disease, severe and fatal cases of malaria occur every year. The majority of malaria cases occur in travelers who did not take prophylaxis. Therefore, there is a tendency to blame them for their severe disease. However, malaria morbidity and mortality increases with any delay in diagnosis and treatment. Hence, it should be emphasized, that there are three links to this chain: the patient who did not take malaria prophylaxis, the physician who failed to consider malaria as the diagnosis of a febrile patient who had just returned from an endemic area, and finally, the hospitals that usually do not store anti-malarial medication. Action should therefore be taken on three levels: first and most easily remedied--hospitals should have anti-malarial medication available by law. Second are the physicians who must be educated with regard to the risk of malaria in returning travelers, and methods of diagnosis. Thirdly, efforts must continue to increase compliance of malaria prophylaxis among travelers to endemic areas.
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Myiasis is an infestation of human tissue by the larvae of certain flies. There are many forms of myiasis, including localized furuncular myiasis, creeping dermal myiasis and wound and body cavity myiasis.1 Cordylobia anthropophaga (the Tumbu fly) and Dermatobia hominis (the human botfly) are the most common causes of myiasis in Africa and tropical America respectively. The genus Cordylobia also contains two less common species, C. ruandae and C. rodhaini. The usual hosts of C. rodhaini are various mammals (particularly rodents), and and humans are accidentally infested. Figure 1 shows the life cycle of C. rodhaini, which occurs over 55 to -67 days.3 The female fly deposits her eggs on dry sand polluted with the excrement of animals or on human clothing. In about 3 days, the larva is activated by the warm body of the host, hatches and invades the skin. As the larva matures, it induces a furuncular swelling. In 12 to -15 days, the larva reaches a length of about 23 mm, exits the skin and falls to the ground to pupate. The adult fly emerges in 23 to -26 days, and the life cycle resumes. In humans, the skin lesion starts as a red papule that gradually enlarges and develops into a furuncle. In the center of the lesion an opening forms, through which the larva breaths and discharges its serosanguinous feces. The lesion is associated with increasing pain until the larva exits the skin. The disease is usually uncomplicated and self-limiting.