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.
During the years 1831-1918 Israel (Palestine at that time) suffered from repeated cholera epidemics. The cholera epidemics were the major cause of severe health crisis among the population. The epidemics were transmitted by returening pilgrims returning from Mecca and, during the first world War, by the Turkish soldiers crossing the country. The disease caused panic amongst the population due to its high mortality rate. Quarantine which was the major measure taken by the government at that time was repeatedly broken by people trying to escape from the affected area. During the epidemic of 1902, patients were even reluctant to be treated by physicians as they were blamed for causing death. On the other hand, cholera was a major trigger for maintaining a better sanitation and establishing social relief systems within the communities. Most of the epidemics occurred in the old cities such as Jerusalem, Tiberia and Jaffa where infrastructure was inadequate. Cholera outbreaks were the trigger to build outside the old cities as in case of Jerusalem in which after the 1865 outbreak the city was expanded outside the walls. Since the end of the Ottoman period in Israel, cholera epidemics ceased, and except for very small occeasional small outbreaks, cholera is not seen here more.
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BACKGROUND: Malaria is a common and important infection in travelers. METHODS: We have examined data reported to the GeoSentinel surveillance network to highlight characteristics of malaria in travelers. RESULTS: A total of 1140 malaria cases were reported (60% of cases were due to Plasmodium falciparum, 24% were due to Plasmodium vivax). Male subjects constituted 69% of the study population. The median duration of travel was 34 days; however, 37% of subjects had a travel duration of < or =4 weeks. The majority of travellers did not have a pretravel encounter with a health care provider. Most cases occurred in travelers (39%) or immigrants/refugees (38%). The most common reasons for travel were to visit friends/relatives (35%) or for tourism (26%). Three-quarters of infections were acquired in sub-Saharan Africa. Severe and/or complicated malaria occurred in 33 cases, with 3 deaths. Compared with others in the GeoSentinel database, patients with malaria had traveled to sub-Saharan Africa more often, were more commonly visiting friends/relatives, had traveled for longer periods, presented sooner after return, were more likely to have a fever at presentation, and were less likely to have had a pretravel encounter. In contrast to immigrants and visitors of friends or relatives, a higher proportion (73%) of the missionary/volunteer group who developed malaria had a pretravel encounter with a health care provider. Travel to sub-Saharan Africa and Oceania was associated with the greatest relative risk of acquiring malaria. CONCLUSIONS: We have used a global database to identify patient and travel characteristics associated with malaria acquisition and characterized differences in patient type, destinations visited, travel duration, and malaria species acquired.
OBJECTIVE: To compare the tolerability of malaria chemoprophylaxis regimens in non-immune travellers. DESIGN: Randomised, double blind, study with placebo run-in phase. SETTING: Travel clinics in Switzerland, Germany, and Israel. MAIN OUTCOME MEASURE: Proportion of participants in each treatment arm with subjectively moderate or severe adverse events. PARTICIPANTS: 623 non-immune travellers to sub-Saharan Africa: 153 each received either doxycycline, mefloquine, or the fixed combination chloroquine and proguanil, and 164 received the fixed combination atovaquone and proguanil. RESULTS: A high proportion of patients reported adverse events, even in the initial placebo group. No events were serious. The chloroquine and proguanil arm had the highest proportion of mild to moderate adverse events (69/153; 45%, 95% confidence interval 37% to 53%), followed by mefloquine (64/153; 42%, 34% to 50%), doxycycline (51/153; 33%, 26% to 41%), and atovaquone and proguanil (53/164; 32%, 25% to 40%) (P = 0.048 for all). The mefloquine and combined chloroquine and proguanil arms had the highest proportion of more severe events (n = 19; 12%, 7% to 18% and n = 16; 11%, 6% to 15%, respectively), whereas the combined atovaquone and proguanil and doxycycline arms had the lowest (n = 11; 7%, 2% to 11% and n = 9; 6%, 2% to 10%, respectively: P = 0.137 for all). The mefloquine arm had the highest proportion of moderate to severe neuropsychological adverse events, particularly in women (n = 56; 37%, 29% to 44% versus chloroquine and proguanil, n = 46; 30%, 23% to 37%; doxycycline, n = 36; 24%, 17% to 30%; and atovaquone and proguanil, n = 32; 20%, 13% to 26%: P = 0.003 for all). The highest proportion of moderate or severe skin problems were reported in the chloroquine and proguanil arm (n = 12; 8%, 4% to 13% versus doxycycline, n = 5; 3%, 1% to 6%; atovaquone and proguanil, n = 4; 2%, 0% to 5%; mefloquine, n = 2; 1%, 0% to 3%: P = 0.013). CONCLUSIONS: Combined atovaquone and proguanil and doxycyline are well tolerated antimalarial drugs. Broader experience with both agents is needed to accumulate reports of rare adverse events.
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.
BACKGROUND: Imported malaria is an important problem in nonendemic countries due to increasing travel to and immigration from malaria-endemic countries. Plasmodium vivax malaria is relatively common in travelers but there are few published data regarding the outcome of P. vivax malaria in this group. METHODS: We analyzed 209 cases of P. vivax malaria that were reported to the GeoSentinel network and the VIDS database, Royal Melbourne Hospital. Analyses were performed on data including demographics, pretravel encounter, antimalarial prophylaxis, exposure history, type of travel, countries of recent and past travel, clinical presentation, treatment, outcome and final diagnoses. RESULTS: The majority of patients were travelers (61%), followed by expatriates (13%) and recent immigrants or foreign visitors (12%). Recent travel to Oceania, sub-Saharan Africa, and South and Central America was significantly more likely to be associated with P. vivax malaria than travel to all other regions. The clinical presentation of P. vivax malaria acquired in the Pacific region is indistinguishable from infection with P. falciparum. The use of chloroquine prophylaxis did not prolong the incubation period. Relapse of infection was not infrequent, and the only significant predictor of relapse was travel to Papua New Guinea (PNG), regardless of primaquine dose. Travelers returning from PNG were eight times more likely to relapse after primaquine treatment compared to travelers with P. vivax malaria acquired elsewhere. CONCLUSIONS: We have presented details of the epidemiology, clinical presentation and management of infection with P. vivax malaria in travelers. P. vivax malaria is an important cause of morbidity in travelers, and relapse following primaquine treatment is especially problematic with P. vivax malaria acquired in PNG.
BACKGROUND: Adventure trips to Africa have become more frequent, and rafting on some of the great rivers has become almost commonplace. We describe three rafting trips on the Omo River in Ethiopia, after which most of the participants were diagnosed with schistosomiasis. METHODS: After index cases from the three groups came to medical attention, active surveillance detected outbreaks of illness in a group of American travelers (n = 18 ) in 1993 and in two groups of Israeli travelers in 1997 (n = 26). RESULTS: Of 44 travelers, 37 were screened and 28 (76%) were infected, all with Schistosoma mansoni. Among the infected patients, 16 of 28 (57%) were symptomatic, the most frequent manifestation being fever, which occurred in 14 of 25 (56%); cough occurred in 6 of 18 (33%). Diagnosis was based on FAST-enzyme-linked immunosorbent assay, with confirmation by immunoblot. Other rafting trips on the Omo River sponsored by the same tour companies did not result in symptomatic infection. Investigation of the rafting itineraries suggested the route may have been altered from the usual for these three groups, exposing them to a part of the river that is wider, slower moving, and more densely populated. CONCLUSIONS: Schistosomiasis should be considered in febrile patients following rafting trips in schistosome-endemic areas. As asymptomatic schistosomiasis in travelers is also common (43% in this series), all travelers exposed to freshwater in endemic areas should be encouraged to undergo serologic screening.