CarlosC. Campbell

Effect of blood transfusion on survival among children in a Kenyan hospital

In Africa, blood transfusions are frequently given to treat severe paediatric anaemia. Because of the risk of HIV transmission, identification of when transfusion will reduce the risk of death for severely anaemic children has become increasingly important. For all children admitted to a Kenyan hospital from October, 1989, to October, 1990, we collected data on clinical presentation, haemoglobin (Hb), receipt of transfusion, and in-hospital survival. Of 2433 admissions, 29% (684) had severe anaemia (Hb less than 5.0 g/dl), and 20% (483) received blood transfusions. Based on laboratory criteria only, children with Hb less than 3.9 g/dl who were transfused had lower mortality than those with Hb less than 3.9 g/dl who were not transfused, but this finding applied only to children transfused on the day of admission (odds ratio [OR] 0.30; 95% Cl 0.14, 0.61) or the day after admission (OR 0.37; 95% Cl 0.14, 1.00). Based on a combination of laboratory and clinical criteria, children with clinical signs of respiratory distress and Hb less than 4.7 g/dl who were transfused had lower morality than those who were not (OR 0.19; 95% Cl 0.09, 0.41). Among children without respiratory distress, there was no association between receipt of transfusion and mortality, irrespective of admission Hb. The frequency of blood transfusion can be reduced and survival enhanced by targeting blood to those children with severe anaemia and clinical signs of respiratory distress, and by using transfusion early in the course of hospitalisation.

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.

Chloroquine-resistant Plasmodium falciparum from East Africa: cultivation and drug sensitivity of the Tanzanian I/CDC strain from an American tourist.

A strain of Plasmodium falciparum, designated Tanzanian I/CDC, from an American tourist returning from Tanzania, was isolated in vitro and in the Aotus monkey. Clinically, the infection showed a late recrudescent pattern of chloroquine resistance. In 2 inoculated Aotus monkeys, the infection recrudesced after a dose of chloroquine (40 mg/kg) curative for sensitive P. falciparum strains in the Aotus monkey. In 4 ,dditional monkeys two primary infections and one of the recrudescent parasitaemias were cured with a 100 mg/kg dose of chloroquine; the second recrudescent parasitaemia was cured with an additional 40 mg/kg dose of chloroquine. The 48 h in-vitro chloroquine-sensitivity test demonstrated that the Tanzanian I/CDC strain had a pattern of chloroquine resistance similar to a reference resistant strain, the Vietnam-Oak Knoll (FVO). These studies reinforce reports which suggest that chloroquine-resistant malaria is being transmitted in East Africa.

Usefulness of clinical case-definitions in guiding therapy for African children with malaria or pneumonia

The World Health Organisation has developed disease-specific clinical case-definitions to guide management of children with fever or cough, the cardinal signs of malaria and pneumonia. To assess the usefulness of the case-definitions and to investigate their interaction, we studied children with fever or cough brought to a hospital in Lilongwe, Malawi. For all children, a thick blood smear was examined for Plasmodium falciparum parasites. Chest radiography was done only for children with parasitaemia and those who satisfied the clinical case-definition for pneumonia; others were assumed to have normal chest radiographs. Of 1599 enrolled children, 566 (35%) had parasitaemia and 116 had radiographic evidence of pneumonia; 43 had both pneumonia and parasitaemia. Of the 471 children who met the clinical definition for pneumonia, 449 (95%) also met the malaria clinical definition. Among children with radiographic evidence of pneumonia, the clinical definition for malaria was not predictive of parasitaemia (sensitivity 93%, specificity 5%). Whether malaria parasitaemia was present or absent, the pneumonia clinical definition distinguished children with and without radiographic evidence of pneumonia (sensitivity and specificity > 60%). Children who satisfied the pneumonia clinical definition were more likely to have radiographic evidence of pneumonia (odds ratio 10.4, 95% confidence interval 5.2-20.7), parasitaemia (1.6, 1.2-2.2), or both at the same time (4.2, 2.1-8.4) than were children who did not meet the definition. Children who satisfy the malaria and pneumonia clinical definitions need treatment for both disorders. Scarce diagnostic methods, especially microscopy, are needed for more specific treatment of children with fever and cough.

Co-trimoxazole for childhood febrile illness in malaria-endemic regions

The efficacy of co-trimoxazole for the treatment of Plasmodium falciparum parasitaemia in children younger than 5 years of age was evaluated in Malawi. 46 children with P falciparum parasitaemia, 37% of whom also met clinical criteria for a diagnosis of acute lower respiratory tract infection, were treated with 20 mg/kg co-trimoxazole twice daily for five days. Parasitaemia (mean clearance time 2.7 days) and symptoms were rapidly abolished and improvement was maintained during follow-up for 14 days. Co-trimoxazole may be an effective single treatment for febrile illness in young children in areas where malaria is endemic, resources are few, and diagnosis must rely on clinical findings alone.

Disease surveillance and decision-making after the 1976 Guatemala earthquake.

In the first 3 weeks after the 1976 earthquake in Guatemala a system for collecting, analysing, and disseminating information of medical importance was instituted in the disaster area. Data on cases of selected diseases, number of available hospital beds, and medical supplies were collected, and reported epidemics were investigated. The system functioned well despite the limited numbers of trained personnel. Collection and analysis were quick enough for data to be used immediately in decision-making. No epidemics of communicable diseases were observed in the affected area. The number of dog bites in Guatemala City increased but no cases of rabies were reported. The success of the surveillance system in Guatemala suggests that immediate use of epidemiological methods should be an integral part of disaster relief.

Mosquito-transmitted malaria in New York City, 1993

In August, 1993, 3 cases of Plasmodium falciparum malaria in people without recent travel histories or bloodborne exposure were reported in New York City. An epidemiological investigation confirmed the absence of risk factors for acquisition of malaria in two cases. The third case could not be definitively classified as locally acquired malaria because the patient had travelled to Thailand two years before malaria was diagnosed. The 3 individuals lived in separate houses in the same neighbourhood of Queens, New York and had onset of illness within a day of each other. The investigation consisted of patient interviews, active case finding, reviewing recent New York flight and shipping arrivals, and an entomological survey for anopheline mosquitoes and breeding sites. No other cases were identified. The 3 patients lived several miles from air and sea ports and prevailing winds would have carried any mosquitoes at those sites away from the patients homes. By the time of the environmental investigation (September, 1993), the area was dry and neither adult nor larval anophelines were found. However, weather conditions at the probable time of infection (July, 1993) were very different. Malaria was probably transmitted to these 2 patients by local anopheline mosquitoes that had fed on infected human hosts. Mosquito-control measures were not implemented because there was no evidence of ongoing transmission. The occurrence of mosquito-transmitted malaria in New York City demonstrates the potential for reintroduction of malaria transmission into areas that are no longer endemic and emphasises the need for continued surveillance and prompt investigations, if cases without risk factors are reported.

IN-VIVO AND IN-VITRO ASSESSMENT OF CHLOROQUINE-RESISTANT PLASMODIUM FALCIPARUM MALARIA IN ZANZIBAR

A population-based field study was conducted in Zanzibar Town, Zanzibar, Tanzania, to assess the in-vivo and in-vitro susceptibility to chloroquine of Plasmodium falciparum. Single-dose therapy with chloroquine (10 mg base/kg) failed to clear parasitaemia in 11 of 22 (50%) treated subjects, and a standard therapeutic regimen of chloroquine (25 mg base/kg) failed to clear parasitaemia in 11 of 32 (34%) treated subjects. Concurrent in-vitro testing by the Rieckmann micromethod showed that 8 of 12 (66%) isolates were chloroquine-resistant.