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H O Lobel

Publications and source records attributed to H O Lobel.

At least 19 recordsLinked to original sources
PubMed1995

Malaria surveillance--United States, 1992.

PROBLEM/CONDITION: Malaria is caused by one of four species of Plasmodium (i.e., P. falciparum, P. vivax, P. ovale, or P. malariae) and is transmitted by the bite of an infective female Anopheles sp. mosquito. Most malaria cases in the United States occur among persons who have traveled to areas that have ongoing transmission. However, cases are transmitted occasionally through exposure to infected blood products, by congenital transmission, or by local mosquito-borne transmission. Malaria surveillance is conducted to identify episodes of local transmission and to guide prevention recommendations. REPORTING PERIOD COVERED: Cases with onset of illness during 1992. DESCRIPTION OF SYSTEM: Malaria cases were identified at the local level (i.e., by healthcare providers or through laboratory-based surveillance). All suspected cases were confirmed by slide diagnosis and then reported to the respective state health department and to CDC. RESULTS: CDC received reports of 910 cases of malaria that had onset of symptoms during 1992 among persons in the United States and its territories. In comparison, 1,046 cases were reported for 1991, representing a decrease of 13% in 1992. P. vivax, P. falciparum, P. malariae, and P. ovale were identified in 51%, 33%, 4%, and 3% of cases, respectively. The species was not identified in the remaining 9% of cases. The number of reported malaria cases that had been acquired in Africa by U.S. civilians decreased 38%, primarily because the number of P. falciparum cases declined. Of U.S. civilians whose illnesses were diagnosed as malaria, 81% had not taken a chemoprophylactic regimen recommended by CDC. Seven patients had acquired their infections in the United States. Seven deaths were attributed to malaria. INTERPRETATION: The decrease in the number of P. falciparum cases in U.S. civilians could have resulted from a change in travel patterns, reporting errors, or increased use of more effective chemoprophylaxis regimens. ACTIONS TAKEN: Additional information was obtained concerning the seven fatal cases and the seven cases acquired in the United States. Malaria prevention guidelines were updated and disseminated to health-care providers. Persons traveling to a malaria-endemic area should take the recommended chemoprophylaxis regimen and use personal protection measures to prevent mosquito bites. Any person who has been to a malarious area and who subsequently develops a fever or influenza-like symptoms should seek medical care, which should include a blood smear for malaria. The disease can be fatal if not diagnosed and treated at an early stage of infection. Recommendations concerning prevention and treatment of malaria can be obtained from CDC.

Female↗
PubMed1994

Malaria in US Marines returning from Somalia.

OBJECTIVE: To identify malaria in US Marines returning from Somalia and to determine their compliance with chemoprophylaxis. DESIGN: Case series. SETTING: The US Navy health care system. PATIENTS: Consecutive sample of 106 US Marines diagnosed with malaria after returning from Somalia in 1993. MAIN OUTCOME MEASURES: Identification of the incidence and clinical features of imported malaria. Determination of compliance with chemoprophylaxis in this cohort. RESULTS: As of December 20, 1993, there were 112 cases of imported malaria in 106 US Marine Corps personnel returning from Somalia. Plasmodium vivax accounted for 97 (87%) of 112 malaria cases, and Plasmodium falciparum accounted for eight (7%) of 112 cases. Mixed infection with P vivax and P falciparum was noted in six (5%) of 112 cases, and a single case of Plasmodium malariae was identified. Patients with P falciparum malaria were diagnosed a mean of 20.9 days (range, 1 to 82 days) after returning to the United States compared with 91.8 days (range, 7 to 228 days) for P vivax infection (P < .0001). The self-reported chemoprophylaxis compliance rate was 56%; however, only 45 (50%) of 90 patients were given an optimal chemoprophylaxis regimen. CONCLUSIONS: Noncompliance with personal protective measures and chemoprophylaxis contributed to the largest outbreak of imported malaria in US military personnel since the Vietnam conflict. Since military personnel frequently go on leave after deployment, health care providers throughout the United States must be aware of the presence of imported malaria from Somalia.

Cohort Studies↗
PubMed1994

The China I/CDC strain of Plasmodium malariae in Aotus monkeys and chimpanzees.

Five Aotus monkeys and two chimpanzees were infected with Plasmodium malariae isolated from a patient who acquired her infection approximately 50 years ago. All animals were splenectomized. The chimpanzees supported the highest parasite densities of 22,271/microliters and 18,544/microliters. Three Aotus monkeys with a previous history of infection with P. vivax had maximum parasite counts of from 1,818/microliters to 2,909/microliters, whereas two monkeys not previously infected had maximum parasite counts of 6,908/microliters. The establishment of new isolates in these animals aides the development of diagnostic probes and the identification of areas of antigenic variation within the species.

Aged↗
PubMed1994

A study of polymorphism in the circumsporozoite protein of human malaria parasites.

We have characterized the circumsporozoite (CS) gene sequences of Plasmodium malariae China-1 CDC, isolated recently from a person who was infected 50 years ago in China, and P. vivax Chesson, isolated 48 years ago from a patient who had returned from New Guinea. These protein sequences were compared with the CS protein sequences of recently isolated P. vivax and P. malariae parasites. In a similar manner, we compared the previously characterized CS protein gene of P. falciparum clone 7G8, derived from a Brazilian isolate collected in 1980, with the CS protein genes of recent P. falciparum field isolates. In the case of the P. malariae CS protein gene, with the exception of an additional copy of major (NAAG) and minor (NDAG) repeat sequences and the presence of one copy of NDEG sequence, the China-1 CDC P. malariae parasite is similar to the Uganda-1 CDC isolate of 1982. In the nonrepeat region, changes were noted in two amino acid residues, one of which is also seen in a closely related monkey malaria parasite, P. brasilianum. In the case of P. vivax CS proteins, the nonrepeat region of the protein in Chesson strain shares identity with nearly 71% of the CS clones characterized from field isolates. In the P. falciparum CS proteins, the 7G8 CS protein sequence is identical to 75% of the genes of recent field isolates in the Th1R-N1 region. In the Th2R and Th3R regions, 34% and 55% of the CS clones analyzed, respectively, had changes at two amino acid residues.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Long-term malaria prophylaxis with weekly mefloquine.

The spread of chloroquine-resistant Plasmodium falciparum malaria has led to increased use of mefloquine prophylaxis by US Peace Corps volunteers in sub-Saharan Africa. We compared long-term mefloquine with other drug regimens for effectiveness and tolerance. The incidence of Plasmodium falciparum infections and of adverse reactions was compared in Peace Corps volunteers who took chloroquine weekly, mefloquine weekly, mefloquine every other week, or weekly chloroquine plus daily proguanil. Weekly mefloquine was 94% more effective than chloroquine (95% CI 86% to 97%), 86% more effective than chloroquine plus proguanil (95% CI 67% to 94%), and 82% more effective than prophylaxis with mefloquine when taken every other week (95% CI 68% to 90%). No serious adverse reactions were observed. Mild adverse events were equally frequent in mefloquine users and chloroquine users, and the frequency of these events declined with increasing duration of prophylaxis. Mefloquine is an effective and well-tolerated drug for prophylaxis of malaria by short-term and long-term travellers.

Africa, Western↗
PubMed1991

Effectiveness and tolerance of long-term malaria prophylaxis with mefloquine. Need for a better dosing regimen.

To measure the effectiveness and tolerance of long-term malaria prophylaxis with mefloquine, the incidence of Plasmodium falciparum malaria and of adverse reactions was compared in Peace Corps volunteers in West Africa who took mefloquine every 2 weeks and in volunteers who took chloroquine phosphate weekly. Mefloquine was only 63% more effective than chloroquine; the monthly incidence of P falciparum infections was one case per 100 volunteers who took mefloquine and 2.7 cases per 100 volunteers who took chloroquine. Using daily proguanil (chloroguanide) hydrochloride in addition to chloroquine did not provide additional protection. All mefloquine prophylaxis failures occurred during the second week of the every-2-weeks dosing regimen in volunteers who had used mefloquine for more than 2 months. Blood concentrations of mefloquine were lower during the second week of the alternate-week regimen than during the first week, suggesting that blood levels are too low during the second week to suppress parasitemia. No serious adverse reactions were observed. The results indicate that a dosing regimen of 250 mg of mefloquine weekly should be considered for travelers to areas with chloroquine-resistant P falciparum malaria.

Adult↗
PubMed1991

Imported Plasmodium falciparum malaria in American travelers to Africa. Implications for prevention strategies.

Data from the US National Malaria Surveillance System were analyzed to assess characteristics of travelers who acquired Plasmodium falciparum infections in Africa and evaluate the impact of chloroquine resistance on the incidence of imported malaria. Although the number of cases acquired in East Africa has stabilized, the number of imported P falciparum infections acquired in West Africa increased threefold from 1985 to 1988, and the proportion of travelers who reported failure of chloroquine prophylaxis increased from 10% to 48%. Fifty-eight percent of patients who acquired malaria in West Africa had not used chemoprophylaxis. To curb the rising incidence of P falciparum infections in American travelers, the Centers for Disease Control revised malaria prophylaxis recommendations to include the use of mefloquine in areas of chloroquine resistance. Use of malaria protection measures by travelers to West Africa must also be improved.

Africa, Eastern↗
PubMed1990

Transmission of Plasmodium vivax malaria in San Diego County, California, 1986.

Between 18 June and 20 September 1986, 28 cases of Plasmodium vivax malaria were documented in Carlsbad, California, a coastal town north of San Diego. Malaria occurred in 1 local resident who had no risk factors, a second local resident who had traveled to a malarious area 9 months earlier, and 26 Mexican migrant workers (MWs). Among the 28 cases, 27 lived in a square mile marshy area where Anopheles hermsi, a newly described American species of the Anopheles maculipennis group, was known to be breeding. An investigation of MWs residing in the affected area was done to determine the extent of the outbreak and to identify risk factors for acquiring malaria. We interviewed and drew blood from 304 healthy MWs and 17 (65%) of the MWs with malaria. Fluorescent antibody titers to P. vivax greater than or equal to 1:256 occurred in 14 (82%) of the 17 MWs with malaria tested and 9 (3%) of the healthy MWs. The principal risk factor identified for contracting malaria was sleeping outside on a hillside adjacent to the marshy area. Malaria in a local resident with no malaria risk factors and the clustering in time and place of 26 cases suggest that P. vivax malaria was introduced and local transmission was sustained through several generations, producing the largest outbreak of introduced malaria in the United States since 1952.

Adolescent↗
PubMed1990

Malaria incidence and prevention among European and North American travellers to Kenya.

A longitudinal survey was conducted among travellers departing from Nairobi airport to determine the use of malaria prevention measures and assess the risk for malaria while travelling in Kenya. Among 5489 European and North American travellers, 68 different drug regimens were used for prophylaxis, and 48% of travellers used both regular chemoprophylaxis and more than 1 antimosquito measure during travel; 52% of 3469 travellers who used chemoprophylaxis did so without interruption during their travel and for 4 weeks after departure. Compliance was lowest among travellers who visited friends and relatives, who were young, or who stayed more than 3 weeks. Sixty-seven (1%) travellers experienced symptoms of malaria, but the diagnosis could be verified for only 16 of these. Long-stay travellers appeared to be at higher risk for malaria than short-stay travellers, and health information needs to be targeted especially to the former. Similar investigations are needed among international travellers to other malaria-endemic countries. With comparable data available, consistent and effective malaria prevention guidelines can be developed.

Adult↗
PubMed1988

A quantitative approach to recommendations on malaria prophylaxis.

In order to develop recommendations for malaria prophylaxis, a quantitative method is needed to balance the risk of Plasmodium falciparum malaria infections against the toxicity of antimalarial drugs. Using decision analysis, we estimated the expected mortality associated with three alternative regimens of prophylactic drugs for visitors to three areas with different risks of infection with chloroquine-resistant P. falciparum. The model used took into account the risks of malaria and of adverse reactions to antimalarial drugs. Estimates of the parameters used in the analysis were based on observations made on U.S. travellers. Reducing the risk of malaria infection was found to have a far greater impact on lowering the expected mortality than that of increasing the chemoprophylactic efficacy of the drugs used, thereby emphasizing the need for travellers to use anti-mosquito measures in malarious areas. The analytical method described can be used to define optimal malaria prevention strategies.

Animals↗
PubMed1987

Efficacy of malaria prophylaxis in American and Swiss travelers to Kenya.

The protective effect of malaria chemoprophylaxis with either Fansidar (pyrimethamine-sulfadoxine) or chloroquine was estimated by determining the attack rates of Plasmodium falciparum infections acquired in Kenya and imported by U.S. and Swiss travelers who had used no chemoprophylaxis, who had used only chloroquine for prophylaxis, and who had used Fansidar weekly, either alone or in combination with chloroquine. The estimated attack rates were almost identical in U.S. and Swiss travelers. The attack rate per 100,000 travelers averaged 280 in those who did not use chemoprophylaxis, 162 in those who took 4-aminoquinolines (P greater than .05), and 27 in those who used Fansidar for prophylaxis (P less than .001). Non-immune travelers to Kenya have an appreciable risk of acquiring a P. falciparum infection and need to be informed of current guidelines for chemoprophylaxis. The changing drug susceptibility patterns in Africa require continuous evaluation of the efficacy of recommended drug regimens for malaria prophylaxis.

Aminoquinolines↗
PubMed1986

Severe cutaneous reactions among American travelers using pyrimethamine-sulfadoxine (Fansidar) for malaria prophylaxis.

In 1982, the fixed combination of pyrimethamine and sulfadoxine (Fansidar) became available in the United States, and was recommended for use in travelers at risk of acquiring chloroquine-resistant Plasmodium falciparum. Prior to that time, no reports of severe cutaneous reactions had appeared in the medical literature despite widespread use for more than 8 years in both Europe and malarious areas of the developing world. In the fall of 1984, the Centers for Disease Control received reports of 4 cases of toxic epidermal necrolysis (including 3 fatalities) among Americans who had used pyrimethamine-sulfadoxine (PYR/SDX) for the prevention of malaria. Subsequent investigation into severe cutaneous reactions associated with the use of this drug by American travelers detected 24 cases of erythema multiforme, Stevens-Johnson syndrome, or toxic epidermal necrolysis. Twenty-three of the 24 patients concurrently used chloroquine. Seven patients died. No risk factors in the development of these reactions other than the use of PYR/SDX could be identified. Among American travelers, we estimate that these reactions occur in 1 per 5,000-8,000 users, and that fatal reactions occur in 1 per 11,000-25,000 users. This higher than expected incidence necessitates that the use of PYR/SDX for the prevention of malaria be reconsidered. In the United States it is now recommended that the routine weekly use of the drug be reserved for those travelers at highest risk of acquiring chloroquine-resistant P. falciparum, when alternate prophylactic regimens are not deemed appropriate.

Adolescent↗