Mortality rates and recurrent rates of tuberculosis in patients with smear-negative pulmonary tuberculosis and tuberculous pleural effusion who have completed treatment

SETTING

Queen Elizabeth Central Hospital, Blantyre, and Zomba Central Hospital, Zomba, Malawi.

OBJECTIVE

To follow-up human immunodeficiency virus (HIV) seropositive and HIV-seronegative patients with smear-negative pulmonary tuberculosis (PTB) and pleural TB who had completed treatment with two different regimens in Blantyre and Zomba, and to assess rates of mortality and recurrent TB.

DESIGN

Patients with smear-negative and pleural TB who had completed 8 months ambulatory treatment in Blantyre or 12 months standard treatment in Zomba and who were smear and culture negative for acid-fast bacilli at the completion of treatment were actively followed every 4 months for a total of 20 months.

RESULTS

Of 248 patients, 150 with smear-negative PTB and 98 with pleural TB, who completed treatment and were enrolled, 205 (83%) were HIV-positive. At 20 months, 145 (58%) patients were alive, 85 (34%) had died and 18 (7%) had transferred out of the district. The mortality rate was 25.7 per 100 person-years, with increased rates strongly associated with HIV infection and age >45 years. Forty-nine patients developed recurrent TB. The recurrence rate of TB was 16.1 per 100 person-years, with increased rates strongly associated with HIV infection, having smear-negative PTB and having received 'standard treatment'.

CONCLUSION

High rates of mortality and recurrent TB were found in patients with smear-negative PTB and pleural effusion during 20 months of follow-up. TB programmes in sub-Saharan Africa must consider appropriate interventions, such as co-trimoxazole and secondary isoniazid prophylaxis, to reduce these adverse outcomes.

Efficacy of an unsupervised ambulatory treatment regimen for smear-negative pulmonary tuberculosis and tuberculous pleural effusion in Malawi

SETTING

Queen Elizabeth Central Hospital, Blantyre, and Zomba Central Hospital, Zomba, Malawi.

OBJECTIVE

To evaluate treatment outcome of unsupervised ambulatory treatment (2R3H3Z3/2TH[EH]/4H) in Blantyre and 'standard' treatment (1STH[SEH]/11TH[EH]) in Zomba in human immunodeficiency virus (HIV) seropositive and seronegative patients with smear-negative pulmonary tuberculosis (PTB) and pleural TB.

DESIGN

All patients with smear-negative and pleural TB registered between 1 April and 31 December 1995 were assessed for enrolment in the study. Study patients were followed up and 12-month treatment outcomes were recorded.

RESULTS

A total of 434 patients, 296 with smear-negative PTB and 138 with pleural TB, were enrolled: 366 (84%) of patients were HIV-positive; 220 (51%) completed treatment, and 144 (33%) died by 12 months. In patients from Blantyre and Zomba, baseline characteristics were similar, apart from older age in those from Zomba, and the proportion of patients who completed treatment and who died were similar. In both sites, significantly higher case fatality rates were found in older patients, HIV-positive patients and patients with pulmonary parenchymal lung disease.

CONCLUSION

Unsupervised ambulatory treatment evaluated in this study had an efficacy similar to that of 'standard' treatment. For operational reasons, however, it will not be recommended for widespread use in Malawi's National Tuberculosis Control Programme.

Cerebral malaria in Malawian children hospitalized with Plasmodium falciparum infection

A hospital-based, prospective study was undertaken at Mangochi District Hospital (MDH) and Kamuzu Central Hospital (KCH) in Malawi. The malaria-transmission patterns in the catchment areas of these two hospitals are very different, transmission being continuous around MDH and seasonal, occurring mostly during the rainy season, around KCH. The main purpose of the study was to determine and compare the prevalences of cerebral malaria (CM) among young, hospitalized children (aged < 5 years) at both sites. Among 8600 of such children admitted to the two hospitals, the overall prevalence of CM was 2.3% (2.2% at KCH and 2.5% at MDH). The prevalences of CM on admission were similar at the two sites during the rainy season (at 3.2%), but the prevalence at MDH during the dry season was statistically higher than that at KCH over the same period (2.1% v. 1.0%; P = 0.0078). A nearly significant difference was noted between the two sites in the prevalences of parasitaemia on admission (11.9% at KCH v. 9.2% at MDH; P = 0.07), and of severe malarial anaemia (SMA) on admission (5.4% at KCH v. 4.2% at MDH; P = 0.06). No inter-site differences were noted in the prevalences of CM or SMA when analysed by mean age, weight, haemoglobin, body temperature, weight-for-age Z-scores, duration of hospitalization, or proportion with high parasite score on admission. These findings differ from those by researchers in other parts of sub-Saharan Africa, where the prevalence of CM has been found to be higher in areas with seasonal transmission patterns. It appears that the epidemiology of CM can differ within the same country, with location and season. Whenever possible, therefore, plans to control CM in any sub-Saharan country should be based on locally generated data.

The effect of Plasmodium falciparum malaria on HIV-1 RNA blood plasma concentration

OBJECTIVES

This study was undertaken to determine the relative effect of malaria infection on HIV concentration in blood plasma, and prospectively to monitor viral concentrations after antimalarial therapy.

DESIGN

A prospective, double cohort study was designed to compare the blood HIV-1 RNA concentrations of HIV-positive individuals with and without acute malaria illness. Subjects were followed for 4 weeks after successful malaria therapy, or for 4 weeks from enrollment (controls).

METHODS

Malawian adults with symptomatic Plasmodium falciparum parasitemia (malaria group) and asymptomatic, aparasitemic blood donors (control group) were tested for HIV-1 antibodies to identify appropriate study groups. The malaria group received antimalarial chemotherapy only and were followed with sequential blood films. In both groups, blood plasma HIV-1 RNA viral concentrations were determined at enrollment and again at 1, 2 and 4 weeks.

RESULTS

Forty-seven malaria patients and 42 blood donors were enrolled. At enrollment blood plasma HIV-1 RNA concentrations were approximately sevenfold higher in patients with malaria than in blood donors (medians 15.1 x 10(4) and 2.24 x 10(4) copies/ml, respectively, P = 0.0001). No significant changes in median HIV-1 concentrations occurred in the 21 blood donors followed to week 4 (P = 0.68). In the 27 subjects successfully treated for malaria who were followed to week 4, a reduction in plasma HIV-1 RNA was observed from a median of 19.1 x 10(4) RNA copies/ml at enrollment, to 12.0 x 10(4) copies/ml at week 4, (P = 0.02). Plasma HIV-1 concentrations remained higher in malaria patients than controls (median 12.0 x 10(4) compared with 4.17 x 10(4) copies/ml, P = 0.086).

CONCLUSIONS

HIV-1 blood viral burden is higher in patients with P. falciparum malaria than in controls and this viral burden can, in some patients, be partly reduced with antimalarial therapy.

Management of pulmonary tuberculosis suspects with negative sputum smears and normal or minimally abnormal chest radiographs in resource-poor settings

SETTING

Queen Elizabeth Central Hospital, Blantyre, Malawi.

OBJECTIVES

1) To determine the proportion of pulmonary tuberculosis (PTB) suspects with negative sputum smears and a normal/minimally abnormal chest radiograph (CXR) who are culture-positive for Mycobacterium tuberculosis, and 2) to determine how many develop smear or radiographic evidence of PTB (TB CXR) during follow-up.

METHODS

PTB suspects with negative sputum smears and a normal/minimally abnormal CXR were given a second course of antibiotics and followed up at 3-week intervals over 3 months with repeat sputum smears and chest radiography.

RESULTS

Of 79 patients (38 men and 41 women, mean age 33 years) with negative smears and a normal/minimally abnormal CXR, 16 (21%) were culture-positive for M. tuberculosis. Of 15 culture-positive patients who were alive and attended follow-up, seven (47%) developed a TB-CXR by 3 months. Of 41 culture-negative patients who were alive and attended follow-up, 13 (32%) developed a TB-CXR, including one patient who became sputum smear-positive. TB-CXRs were found only in patients with a cough.

CONCLUSION

TB suspects with negative smears and normal/minimally abnormal CXRs in high human immunodeficiency virus (HIV) prevalent countries should be given a second course of antibiotics. If cough improves, patients can be advised not to return for further follow-up. If cough continues, patients should return for further follow-up with sputum smear examination and chest radiography. Approximately 50% of those who have culture-positive PTB will develop a TB-CXR by 3 months and can be identified if radiographic facilities are available.

Treatment outcome of an unselected cohort of tuberculosis patients in relation to human immunodeficiency virus serostatus in Zomba Hospital, Malawi

There is little information about treatment outcome in patients with smear-negative pulmonary tuberculosis (PTB) or extrapulmonary tuberculosis (EPTB) treated under routine programme conditions in subsaharan Africa. A prospective study was carried out to determine treatment outcome in an unselected cohort of TB patients admitted to Zomba General Hospital, Malawi. Eight hundred and twenty-seven adult TB patients (451 men and 376 women) were registered between 1 July and 31 December 1995. Standardized treatment outcomes of treatment completion, death, default, and transfer to another district were assessed in relation to type of TB, human immunodeficiency virus (HIV) serostatus, age and gender. Two hundred and fifty-four patients (31%) died by the end of treatment, half of the deaths occurring in the first month. Death rates were 19% among 386 patients with smear-positive PTB, 46% among 211 patients with smear-negative PTB, and 37% among 230 patients with EPTB; 77% of the patients were HIV seropositive. Among new patients, HIV-positive patients had higher death rates than HIV-negative patients (hazard ratio [HR] 2.5; 95% confidence interval [95% CI] 1.6-3.8). Smear-negative patients had the highest death rates (HR 3.9; 95% CI 2.7-5.5 compared to smear-positive patients), followed by EPTB patients (HR 2.6, 95% CI 1.8-3.7 compared to smear-positive patients). Death rates increased with age but were similar in men and women. Adult patients in Malawi with smear-negative PTB and EPTB have low treatment completion and high death rates, related to high levels of HIV infection. National TB control programmes in areas of high HIV prevalence should no longer ignore treatment outcomes in patients with smear-negative PTB or EPTB.

Prevalence of tuberculosis in TB suspects with short duration of cough

The prevalence of pulmonary tuberculosis (PTB) in patients with short duration of cough was determined. Ninety-eight adult out-patients (60 men, 38 women; mean age 32 years) at Queen Elizabeth Central Hospital, Blantyre, Malawi, who had cough for 1-3 weeks which was unresponsive to a course of antibiotics, were successfully screened by microscopy and culture of 2 or 3 sputum specimens and chest radiography; 34 (35%) had PTB. Ten patients were sputum smear-positive and 24 were smear-negative and culture-positive. There was no difference in age, gender or clinical features of general illness, respiratory disease and HIV-related disease between patients with PTB and those with no evidence of PTB. Nine patients (26%) with microbiologically confirmed tuberculosis (TB) had chest radiograph abnormalities consistent with TB, compared with 5 (8%) of patients with no microbiological evidence of TB. Certain classes of patients with a short history of cough would benefit from PTB screening strategies with the emphasis on sputum examination rather than chest radiography, which is unreliable in such patients. The classes include (i) patients with other features of TB whose cough has not improved with antibiotic therapy, (ii) seriously ill patients, and (iii) patients in high risk institutions such as prisons and refugee camps.

The scourge of HIV-related tuberculosis: a cohort study in a district general hospital in Malawi

Malawi is similar to a number of other African countries in having an escalating, HIV-related, tuberculosis (TB) epidemic. A prospective study was carried out to determine the pattern of disease and HIV serostatus in unselected, adult, TB patients consecutively admitted to a large, district general hospital in Zomba (in the Southern region of Malawi). Clinical details were obtained, from the district TB register, for the 714, adult TB patients, aged > or = 15 years, who were registered with the district TB officer between 1 July and 31 December in 1995. Patients were counselled, and offered HIV testing using an ELISA and particle agglutination test. Concordant HIV-test results were available for 686 (96%) of the subjects: 547 (80%) of these were HIV-seropositive and 139 seronegative. The HIV-positive patients were significantly younger than the HIV-negative patients and significantly more HIV-positive patients were males (P < 0.05 for each). The proportions of HIV-positive subjects who were new patients, had been previously treated for TB, had pulmonary TB (PTB), had smear-positive PTB or had different types of extrapulmonary TB were similar to those of the HIV-negative. A high percentage of an unselected cohort of adult TB patients admitted to a district, general hospital in Malawi, particularly of the younger age groups was therefore HIV-positive. The pattern of disease was uninfluenced by the HIV serostatus. The large number of cases registered emphasises the severity of the current epidemic of TB in Malawi and its impact upon young adults.

Screening pulmonary tuberculosis suspects in Malawi: testing different strategies

Alternative strategies for screening tuberculosis (TB) suspects are needed in sub-saharan Africa. Ambulatory adult TB suspects who were seen in the chronic cough room of Queen Elizabeth Central Hospital, Blantyre, Malawi, were assessed with respect to appropriateness of referral. Appropriate referrals (patients with cough 3 weeks or longer, weight loss and no antibiotic response) were screened by 3 sputum specimens for microscopy and culture of Mycobacterium tuberculosis and chest radiography (CXR). Hypothetical strategy A (screening by sputum smear examination followed by CXR in patients with negative sputum smears) was compared with strategy B (screening by CXR followed by sputum smear examination in patients with a CXR consistent with TB) in terms of diagnostic efficacy and cost. Of 1127 patients referred to the cough room, 402 (38%) were appropriate TB suspect referrals. Of these, 111 (28%) were sputum smear-positive, 213 (53%) were culture-positive, and 221 (55%) had smear and/or culture-positive evidence of TB. Routine CXR was consistent with pulmonary (P) TB in 230 patients (57%). With strategy A, 243 (60%) patients were diagnosed as PTB, but 40 (25%) of those not diagnosed as PTB had positive mycobacterial cultures. With strategy B, 230 patients (57%) were diagnosed as PTB, but 53 (31%) of those not diagnosed as PTB had positive mycobacterial cultures, including 13 with smear-positive sputum. The cost per diagnosed case of PTB was US$ 4.63 with strategy A and US$ 5.44 with strategy B. Screening patients with good criteria of TB has high diagnostic sensitivity, but screening by CXR is less effective and more costly than screening by sputum smear microscopy.

Malaria infection in infancy in rural Malawi

Malaria infection is thought to be relatively infrequent in infants less than 90 days of age in sub-Saharan Africa. In a rural area of Malawi with intense malaria transmission, we examined the occurrence of malaria infection during infancy and risk factors for parasitemia in the first three months of life in the cohort of infants delivered to women in the Mangochi Malaria Research Project. Among 3,915 liveborn singleton infants, 3,432 (87.7%) were seen at least once during infancy (first 12 months of life); of these, malaria blood smear results were available on 2,649 (77.2%). Overall, in a cross-sectional analysis, 23.3% of infants at three months of age were infected with Plasmodium falciparum; this proportion increased to more than 30% during the high transmission season. By the age of 10 months, 60-80% of the infants were infected, depending on the season. Geometric mean parasite density increased each month after two months of age and plateaued at seven months of age. In a life-table analysis, the median time to acquisition of a positive smear was 199 days. Factors independently associated with smear positivity at < 4 months of age included visit during high transmission season (adjusted odds ratio [AOR] = 4.1), maternal smear positivity at the same visit (AOR = 3.5), history of infant fever in the previous two weeks (AOR = 2.8), birth during the rainy season (AOR = 1.7), low socioeconomic status (AOR = 1.6), and low maternal education (AOR = 1.5). The specificity of a recent fever history for malaria infection in early infancy was high (> 70%). Intervention strategies to reduce the risk of early infant infection need to be targeted toward mothers of infants at high risk.

Impairment of a pregnant woman's acquired ability to limit Plasmodium falciparum by infection with human immunodeficiency virus type-1

In Africa, the human immunodeficiency virus (HIV) is the most serious emerging infection and Plasmodium falciparum malaria is one of the most prevalent infectious diseases. Both infections have serious consequences in pregnant women, their fetuses, and infants. We examined the association between HIV and P. falciparum in pregnant women enrolled in a malaria chemoprophylaxis study in rural Malawi. Pregnant women (n = 2,946) were enrolled at their first antenatal clinic visit (mean 5.6 months of pregnancy), placed on one of three chloroquine regimens, and followed through delivery. Plasmodium falciparum parasitemia was measured at enrollment, monthly thereafter, at delivery, and 2-6 months postpartum; placental and newborn (umbilical cord blood) infection was measured for hospital-delivered infants. Serum collected during pregnancy was tested for antibodies to HIV by enzyme-linked immunoassay with Western blot confirmation. Parasitemia was detected in 46% of 2,946 women at enrollment and 19.1% at delivery; HIV seroprevalence was 5.5%. The prevalence and geometric mean density (GMPD) of parasitemia at enrollment and at delivery were higher in HIV-seropositive(+) than in HIV-seronegative(-) women (at enrollment: 57% prevalence and a GMPD of 1,558 parasites/mm3 versus 44% and 670/mm3, respectively; P < 0.0001; and at delivery: 35% and 1,589/mm3 versus 18% and 373/mm3; P < 0.0005). Placental infection rates were higher in HIV(+) compared with HIV(-) women, (38% versus 23%; P < 0.0005). This association was strongest in multigravidas. Compared with infants born to HIV(-) women, newborns born to HIV(+) women had higher rates of umbilical cord blood parasitemia. Both HIV(+) and HIV(-) women had similar rates of parasitemia 2-6 months postpartum. The HIV infection diminishes a pregnant woman's capacity to control P. falciparum parasitemia and placental and newborn infection, the major determinants of the impact of P. falciparum on fetal growth and infant survival.

Malaria treatment and prevention in pregnancy: indications for use and adverse events associated with use of chloroquine or mefloquine

In sub-Saharan Africa, women frequently report a variety of symptoms during pregnancy, some of which indicate possible illness. Given the adverse impact of malaria in pregnancy, these events may be important for at least two reasons: it may be possible to use reported fever illness as a determinant of which women need an antimalarial intervention, and, it is possible that adverse symptoms following the antimalarial intervention may be important determinants of continued adherence to the prevention regimen. In a cohort of pregnant women enrolled at first antenatal clinic visit in rural Malawi, we evaluated reported fever, determined parasitemia, and placed the women on antimalarial regimens containing chloroquine (CQ) or mefloquine (MQ). We then systematically evaluated reported symptoms following antimalarial drug use after initial therapeutic doses and subsequent prophylactic doses, and monitored women throughout their pregnancy and at delivery. Among 4,187 enrolled women, 1,048 (25%) reported at least one febrile episode during pregnancy before their first antenatal clinic visit. Factors associated with this reported fever included low parity, enrollment in the rainy season, human immunodeficiency virus seropositivity, use of antimalarial prophylaxis before enrollment, high socioeconomic status, normal (compared to low) maternal height and weight, and literacy. Fever before the first antenatal clinic visit was reported by 24.4% of parasitemic women and 25.4% of aparasitemic women; the sensitivity and specificity of fever to identify parasitemic women was 24% and 71%, respectively. In contrast, the sensitivity and specificity of first or second pregnancy to identify parasitemic women was 71% and 57%, respectively. Among women on a CQ or MQ regimen, approximately 60% reported side effects (e.g., itching, dizziness, and gastrointestinal disturbances) after a treatment dose and approximately 25% reported side effects after a prophylactic dose; rates and types of symptoms reported were similar in the CQ and MQ groups. Few serious side effects were observed and rates of fetal loss were low and similar in the groups. Reliance on fever illness will be wholly inadequate to identify parasitemic women; therefore, our findings support existing World Health Organization recommendations that presumptive treatment and prevention regimens should be offered to all pregnant women. When resources are inadequate to offer antimalarial prophylaxis to all pregnant women, women in their first or second pregnancy may be a more appropriate target group than pregnant women with reported fever. Education regarding expected minor side effects may reduce rates of poor compliance and improve the effectiveness of the prevention effort.

Objectives and methodology in a study of malaria treatment and prevention in pregnancy in rural Malawi: The Mangochi Malaria Research Project

Malaria infection due to Plasmodium falciparum has been widely recognized as associated with important adverse consequences in pregnant women, particularly in areas of high transmission. Although strategies using antimalarial drugs for prevention had been recommended, even by the late 1980s, few studies had been carried out to examine the efficacy of these prevention efforts. The objectives of the Mangochi Malaria Research Project investigation were to determine the comparative efficacy of regimens containing chloroquine (CQ) or mefloquine (MQ) antimalarial treatment and chemoprophylaxis in an area of CQ-resistant P. falciparum on the following outcomes: 1) the frequency of placental malaria infection; 2) the frequency of low birth weight; 3) the frequency of prematurity or intrauterine growth retardation; 4) the frequency of maternal fever illness and severe anemia; and 5) the likelihood of infant acquisition of malaria infection. Although the investigation was not designed to evaluate the role of antimalarial chemoprophylaxis and treatment on infant mortality reduction, because babies born to study women were scheduled to be followed for up to two years of life, the study allowed for an examination of mortality and morbidity in this population. The sample size was insufficient to provide more than descriptive analysis of mortality and morbidity in the fetal, perinatal, neonatal, postneonatal, and infant time intervals. The study design allowed for the evaluation of two additional aspects of maternal and infant health: other determinants of the above-listed outcomes in addition to malaria prevention (e.g., maternal age, gravidity, socioeconomic status, infection with human immunodeficiency virus or syphilis) and reported cause-specific mortality in the fetal-to-infant intervals. The study design included 22 months of enrollment of pregnant women at their first antenatal clinic visit from four clinic sites in Mangochi District, Malawi, with assignment to one of four antimalarial regimens and prospective follow-up through pregnancy, at delivery, and during infancy. All drug dosing was performed under supervision by the study team, making this an evaluation of intervention efficacy (excluding the role of patient compliance).

Comparability of treatment groups and risk factors for parasitemia at the first antenatal clinic visit in a study of malaria treatment and prevention in pregnancy in rural Malawi

The problems of Plasmodium falciparum infection in pregnant women have been described in numerous sub-Saharan African countries, but the frequency of parasitemia at the first antenatal visit and risk factors for infection have not been fully investigated. During a prospective antimalarial treatment and prophylaxis trial in pregnant women in Malawi (three groups receiving a chloroquine regimen and one group receiving a mefloquine regimen), we examined women at their first antenatal clinic visit to evaluate these issues and to verify that subjects in the study treatment/prevention arms were similar. Among 4,127 women with enrollment blood smear results, 1,836 (44.5%) were parasitemic. The highest infection rates and densities were observed in primigravidas (66% infected, geometric mean parasite density [GMPD] = 1,588 parasites/mm3 of whole blood), followed by second pregnancies (46% infected, GMPD = 615 parasites/mm3) and subsequent pregnancies (29% infected, GMPD = 238 parasites/mm3), (P < 10(-6) for both infection prevalence and density, by chi-square test for trend). Significant risk factors for parasitemia at first antenatal clinic visit in a multivariate model included low gravidity, high transmission season, no use of prophylaxis before first antenatal clinic visit, young age (< 20 years), human immunodeficiency virus (HIV) infection, low hematocrit, short stature, and second trimester (compared with third trimester). Women in the different treatment arms of the study were generally similar in many characteristics; statistically significant differences, where present, were small. Targeting malaria control efforts to women in their first or second pregnancy and during the high transmission season will be an important strategy to reach most parasitemic women and minimize resource expenditure. Women infected with HIV had a 55% increased risk of parasitemia at their first antenatal clinic visit and may represent an additional important risk group whose numbers may be increasing and who may benefit from identification and management for malaria.

Malaria parasite infection during pregnancy and at delivery in mother, placenta, and newborn: efficacy of chloroquine and mefloquine in rural Malawi

Despite international recommendations to use malaria treatment and prevention in pregnant women in malaria-endemic areas, few studies have evaluated the efficacy of available antimalarial regimens. This issue is of particular concern in the face of spreading chloroquine (CQ)-resistance of Plasmodium falciparum in malarious areas of sub-Saharan Africa. In a prospective trial in rural Malawian pregnant women, we examined three regimens using CQ (including the existing national policy regimen) and one regimen using mefloquine (MQ). The efficacy of the regimens was determined by comparing rates of clearance of initial parasitemia; prevention of breakthrough infection; and parasitemia at delivery in maternal peripheral blood, placental blood, and in infant umbilical cord blood. Among 1,528 parasitemic women at enrollment, 281 (18.4%) had persistent infections; and among 1,852 initially aparasitemic women, 320 (17.3%) had breakthrough parasitemia on one or more follow-up visits. Compared with women on MQ, women on a CQ regimen were at significantly greater risk of persistent and breakthrough infection (odds ratios [OR] = 30.9 and 11.1, respectively, P < 10(-6)). Other significant risk factors for persistent and breakthrough infections in a multivariate model included first pregnancy; enrollment in the rainy or postrainy season; maternal age < or = 25 years; seropositivity to the human immunodeficiency virus (HIV) (persistent infections only); and no use of antimalarial prophylaxis before enrollment (breakthrough infections only). At delivery, compared with women on MQ, women on a CQ regimen were at significantly greater risk of peripheral, placental, or umbilical cord blood parasitemia (OR = 8.7, 7.4, and 4.1, respectively, P < 10(-6)). Additional risk factors for parasitemia at delivery in multivariate models included first pregnancy; delivery in the rainy or postrainy season; HIV-seropositivity; and maternal age < or = 25 years (risk for peripheral and placental blood parasitemia only). Maternal anemia (hematocrit < 30%) at enrollment or at delivery was not associated with persistent or breakthrough parasitemia or parasitemia at deliver in these multivariate models. While factors leading to increased malaria parasite exposure (high transmission seasons) and lowered or altered host immune response (low pregnancy number, young age, and HIV infection) are important risk factors for malaria in pregnant women, the use of an ineffective intervention (CQ in a setting with CQ-resistant parasites) was the most important determinant of P. falciparum parasitemia in these pregnant women. Strategies to reduce the impact of malaria in pregnant women must use efficacious interventions and may need to consider targeting the intervention to the most susceptible women during the seasons of high malaria exposure.

Transplacental transmission of Plasmodium falciparum in rural Malawi

Malaria during pregnancy may result in fetal exposure to malaria when parasites are transmitted across the placenta. To document the rate of transplacental passage of Plasmodium falciparum and to identify the risk factors for congenitally acquired malaria infection, we examined umbilical cord blood for malaria parasites from 2,080 newborn infants born to mothers enrolled in a study of malaria prophylaxis during pregnancy. Cord blood parasitemia was detected in 140 (6.7%) newborn infants with a geometric mean density of 187 parasites/microliter (range 12-99, 752 parasites/microliter). The likelihood of umbilical cord blood parasitemia was closely linked to the parasite density of placental malaria infection and the density of maternal peripheral blood parasitemia at the time of delivery; all babies born to women with both placental and peripheral blood parasitemia densities > or = 10,000/microliter had cord blood parasitemia. In a multivariate logistic regression model, male sex, premature delivery, and placental and maternal peripheral blood malaria parasitemia were independently associated with a baby being born with umbilical cord blood parasitemia. In this setting, highly endemic for malaria, transplacental transmission of malaria from infected placentae occurs frequently and is directly related to the density of maternal malaria infection.

The effect of malaria and malaria prevention in pregnancy on offspring birthweight, prematurity, and intrauterine growth retardation in rural Malawi

While there is broad evidence for the adverse effects of Plasmodium falciparum infection in pregnancy, and the World Health Organization recommends preventive strategies, there is markedly reduced efficacy in sub-Saharan Africa of the most widely available, affordable and used antimalarial drug for chemoprophylaxis-chloroquine (CQ). During 1987-1990, we studied pregnant women in an area of high malaria endemicity in rural Malawi to compare the efficacy of CQ (the drug recommended by national policy) with mefloquine (MQ, a relatively new and highly effective antimalarial) in preventing low birth weight (LBW) due to prematurity and intrauterine growth retardation (IUGR). Among 1,766 women monitored during at least their last six weeks of pregnancy with observed ingestion of their regimen and facility delivery of a live born singleton, their babies had a mean +/- SD birth weight of 2,905 +/- 461 gm and 16.8% had LBW. In a multivariate analysis, factors significantly associated with LBW included: first birth (odds ratio [OR] = 4.27), female infant (OR = 2.92), maternal human immunodeficiency virus infection (OR = 2.66), low maternal weight (OR = 1.95), and placental blood P. falciparum infection (OR = 1.71). Factors significantly associated with IUGR-LBW included first birth, female infant, low maternal weight, and placental malaria. Factors significantly associated with preterm-LBW included maternal syphilis infection, umbilical cord blood malaria, first birth, low maternal weight, and female infant. Use of an effective antimalarial (MQ) was protective against LBW through its effect on reducing placental and umbilical cord blood malaria infection. The proportion of LBW babies born to women on MQ (12.5% [parity-adjusted for the population of delivering women]) was significantly lower than the proportion born to women on CQ (15.5%; P = 0.05). Effective prevention of malaria in pregnant women in malaria-endemic settings may reduce the likelihood of LBW by 5-14%, and may reduce the amount of preventable LBW by more than 30%. When evaluating antenatal care programs, health policy makers must consider providing an effective preventive drug (either MQ or other drugs identified in additional studies, e.g., sulfa-pyrimethamine compounds) as a means to prevent low birth weight and its consequences.

Infant and second-year mortality in rural Malawi: causes and descriptive epidemiology

Community information based on causes and circumstances of death in infants and young children in Malawi was obtained in a prospective cohort of babies delivered to women enrolled in a malaria-prevention-in-pregnancy study. Vital status information was obtained through home visits every two months; for children who died, questions were asked concerning age and date of death, symptoms preceding death, care sought, location of death (home versus facility), and duration of illness. Of 3,274 liveborn singleton infants, 181, 397, and 152 deaths occurred in the neonatal, postneonatal, and second year of life, respectively. For neonates, proportionate mortality was greatest for sepsis/tetanus (16.7%) and fever (8.6%); however, for more than half of neonatal deaths evaluated the cause was not identified. Up to 30% of neonatal deaths may have been related to prematurity. In the postneonatal period, gastrointestinal illness (39.6%), fever (18.3%), and respiratory illness (14.7%) were the leading causes. Most postneonatal illnesses lasted 1 week or less. Two-thirds of postneonatal deaths occurred outside of a health care facility, although 80% were brought to a facility for care during their illness. Infectious disease syndromes continued to be important in the second year of life, with gastrointestinal (31.6%), fever (23.5%), and measles (20.6%) the most commonly reported causes of death. In this area of rural sub-Saharan Africa, neonatal mortality contributes substantially to infant mortality, and prematurity is considered to be an important component of early neonatal deaths; infectious disease syndromes predominate in the postneonatal and second year of life. Strategies to reduce infant deaths in sub-Saharan Africa must consider these factors, as well as the observations that most children who died had brief illnesses, were taken to a health care facility before death, yet died at home.

Rates and risk factors for mortality during the first two years of life in rural Malawi

Developing nations in sub-Saharan Africa experience childhood mortality rates that are much higher than any other region of the world. In a rural Malawian community we investigated risk factors for deaths occurring during the neonatal (birth-28 days), postneonatal (29-365 days), infant (birth-365 days), and second-year (366-730 days) periods among a cohort of 3,724 infants monitored from birth. The neonatal mortality rate in this cohort was 48.6 per 1,000 live births (LB); the postneonatal mortality rate was 108.7/1,000 LB. The overall infant mortality rate was 157.3 deaths/1,000 LB and the mortality rate for the first two years of life was 223.7 deaths/1,000 LB. The predominate risk factors for neonatal deaths identified in multivariate analysis were low (hazard ratio [HR] = 2.3) and very low birth weight (HR = 12.7), first pregnancy (HR = 1.8) and maternal syphilis infection (HR = 2.4). Maternal infection with human immunodeficiency virus (HIV) (HR = 1.5) predominated for postneonatal deaths. Low (HR = 1.4) and very low (HR = 5.0) birth weight, first pregnancy (HR = 1.6), maternal HIV infection (HR = 2.4), and the combination of low education and low socioeconomic status (SES) of the mother (HR = 2.0) were the most important factors during the infant period. Maternal HIV infection (HR = 3.3) and the combination of low education and low SES of the mother (HR = 2.6) were the predominate risk factors for mortality occurring during the second year. Factors that were significant in univariate analysis but not significant in the final multivariate models included prematurity, previous adverse reproductive outcome, dying during high malaria transmission season, and being born at home. Interventions to prevent maternal HIV infection and low birth weight and treatment of syphilis infection would have a great impact on reducing early childhood deaths. Improving the delivery of health care and education to women during their first pregnancy and to the most socially disadvantaged women may also help reduce the burden of early childhood mortality in communities such as the one studied in Malawi.

Evaluation of maternal practices, efficacy, and cost-effectiveness of alternative antimalarial regimens for use in pregnancy: chloroquine and sulfadoxine-pyrimethamine

With the knowledge that an efficacious antimalarial administered to pregnant women would markedly reduce placental malaria and its associated risk of low birth weight (LBW), investigations were conducted to identify an antimalarial regimen practical for nationwide implementation through the antenatal clinic (ANC) system. Maternal practices, including ANC utilization and malaria treatment and prevention during pregnancy were evaluated as part of a national malaria knowledge, attitudes, and practices survey. A second study was conducted to evaluate the efficacy and cost of selected alternative antimalarial regimens. Women in their first or second pregnancy were placed on chloroquine (CQ) treatment (25 mg/kg) followed by weekly CQ (300 mg) (CQ/CQ); sulfadoxine-pyrimethamine (SP) treatment followed by CQ (300 mg weekly) (SP/CQ); or SP treatment during the second trimester and repeated at the beginning of the third trimester (SP/SP). With 87% of women attending ANC two or more times during pregnancy, most pregnant women in Malawi could be reached with an antimalarial intervention. Among 159 women in their first or second pregnancy receiving CQ/CQ, SP/CQ, and SP/SP, placental malaria parasitemia rates were 32%, 26%, and 9%, respectively (P = 0.006, by chi-square test). The SP/SP regimen was also markedly more cost-effective in preventing infant deaths, costing $75 per infant death prevented, compared with $481 for SP/CQ and $542 for CQ/CQ. These investigations suggest that a regimen consisting of two treatment doses of SP during pregnancy is an efficacious and cost-effective intervention to prevent placental malaria, and LBW-associated mortality, that can be delivered to pregnant women through ANCs in settings similar to those found in rural Malawi.

Developing effective strategies for malaria prevention programs for pregnant African women

The control of malaria in pregnant African women, one of several child survival strategies applied through antenatal care, has been particularly challenging. Prevention and control recommendations for typical areas of high Plasmodium falciparum transmission have promoted the use of antimalarial chemoprophylaxis to prevent placental infection. Persistently low program coverage coupled with diminishing intervention effectiveness have forced a re-evaluation of the relative importance of malaria in pregnancy. The Mangochi Malaria Research Project (MMRP), a prospective evaluation of malaria prevention in pregnant women in rural Malawi conducted during 1987-1990, contributed to establishing new criteria for policy and program development for malaria prevention in pregnancy. The principle findings of the MMRP include: 1) populations at risk of the adverse consequences of malaria in pregnancy include women with low parity, women infected with human immunodeficiency virus, pregnancy during the high malaria transmission season, and the use of a malaria drug that is suboptimally efficacious; 2) the estimated maximum benefits of an antimalarial intervention that clears placental and umbilical cord parasitemia are a 5-12% reduction of low birth weight (LBW), an approximately 35% reduction in the risk of LBW for risks that are actually preventable once a woman has become pregnant (e.g., risks such as infectious disease or poor nutrition during gestation), and a 3-5% reduction in the rate of infant mortality; 3) the intervention must be capable of rendering the woman malaria parasite free, including clearance of parasites from the placental vascular space and umbilical cord blood; 4) other diseases adversely affect pregnancy outcome and, while the control of malaria in pregnancy may not warrant independent programming, if coupled with prevention programs to provide a range of antenatal services, the incremental costs of malaria control may prove to be highly cost-effective; and 5) the choice of a regimen must balance intervention efficacy with safety, availability, affordability, and simplicity of delivery, and several antimalarials may meet these criteria. The Malawi Ministry of Health has modified its malaria prevention in pregnancy recommendations and now faces the challenge of effective programming to improve child survival.

The problem of malaria and malaria control in pregnancy in sub-Saharan Africa

Plasmodium falciparum infection in pregnant women frequently leads to placental infection and low birth weight (< 2,500 grams) of the infant, particularly in the areas of high malaria transmission found in sub-Saharan Africa. Low birth weight is widely known to be an important risk factor for early infant mortality. To reduce the risk that maternal infection poses to child survival, many antenatal clinic programs recommend and provide antimalarial chemoprophylaxis, often with chloroquine (CQ) as a recommended element for antenatal care. Prior to the 1980s, despite widespread advocacy for this intervention, little was known about the effect of this intervention strategy. As an introduction to the Mangochi Malaria Research Project, which examined the efficacy of several antimalarial regimens using CQ or mefloquine in pregnant women in Malawi, we describe the background of knowledge regarding malaria infection in pregnant African women and the important elements of an intervention and prevention strategy.

The effect of placental malaria infection on perinatal mortality in rural Malawi

Perinatal deaths (fetal or infant deaths from the 28th week of pregnancy up to the seventh day after birth) occur as a result of adverse conditions during pregnancy, labor, and delivery, or in the first few days of life. Placental malaria infection is known to increase the risk of delivery of a low birth weight infant, thus, potentially increasing the risk of perinatal and infant mortality. To better understand the relationship among the adverse events in pregnancy, including placental malaria infection, adverse conditions in labor, and birth weight to perinatal mortality, we investigated the perinatal mortality among a cohort of infants born to rural Malawian women for whom placental malaria infection status and birth weight were documented. Among the 2,063 mother-singleton infant pairs, there were 111 perinatal deaths (53.8 perinatal deaths per 1,000 births). The risk of perinatal death increased as birth weight decreased. Risk factors identified for perinatal mortality among all infants excluding birth weight included abnormal delivery (cesarean section, breech, or vacuum extraction), a history of a late fetal or neonatal death in the most recent previous birth among multiparous women, reactive maternal syphilis serology, nulliparity, and low socioeconomic status. Placental malaria infection was not associated with increased perinatal mortality, but was associated with lower perinatal mortality among normal birth weight (> or = 2,500 g) infants (odds ratio = 0.35, 95% confidence interval = 0.14, 0.92). Interventions to address these risk factors could have a substantial impact on reducing perinatal mortality in this population.

Prospective assessment of mortality among a cohort of pregnant women in rural Malawi

Maternal mortality has recently received attention as a neglected public health problem in many developing countries where mortality rates are estimated to be 8-200 times those in developed countries. Most maternal mortality estimates in sub-Saharan Africa have used retrospective methods because of the lack of large population-based studies. The Mangochi Malaria Research Project, a trial of antimalarial chemoprophylaxis in pregnant women, provided an opportunity to examine prospectively mortality among the study women. Among 4,053 monitored pregnant women, 27 women were known to have died during pregnancy, labor, delivery and the one-year follow-up period. Three women died during the antenatal period and 12 died within six weeks of delivery for an estimated maternal mortality rate of 370 per 100,000 pregnant women; this rate was consistent with rates reported from retrospective surveys in Malawi. Twelve women died between three and 10 months after delivery, and the mortality rate in this nonmaternal period was estimated to be 341 per 100,000. Mortality rates in the maternal and nonmaternal periods were surprisingly similar. Human immunodeficiency virus type-1 (HIV-1) infection and anemia were strongly associated with death in the nonmaternal period. Mortality among infants of mothers who died was 3.7 times higher than the rate of death among infants born to mothers who survived. This study highlights that for rural Malawian women, pregnancy and delivery are risky periods, that the death of the mother adversely affects the survival of her children, and that HIV and anemia are important contributors to nonmaternal mortality in reproductive-age women. Strategies to reduce mortality among women of child-bearing age in sub-Saharan Africa must focus on decreasing the complications of pregnancy and delivery, and address important preventable causes of death, such as anemia and HIV infection.

Efficacy of sulphadoxine/pyrimethamine for Plasmodium falciparum malaria in Malawian children under five years of age

In March 1993, sulphadoxine/pyrimethamine (SP) replaced chloroquine as the first line drug for malaria treatment in Malawi. Since then, the Ministry of Health has been receiving anecdotal and written reports of SP treatment failures in children. To determine whether treatment failure with SP was a widespread problem, children < 5 years of age with axillary temperature > 38.0 degrees C and parasite density > 2000/mm3 attending the outpatient clinics of the Mangochi and Karonga District Hospitals were enrolled in the study with parental consent. These were then followed for 28 days or until they failed clinically. Of 159 patients enrolled, 145 (91.2%) were followed for 28 days or until clinical failure. Of these, none had RII resistance and 3 (1.9%) had RIII resistance: 2/69 (2.9%) in Mangochi and 1/76 (1.3%) in Karonga; 142/145 (97.9%) exhibited RI/sensitive patterns. Of those followed to day 28 or to clinical failure, 77.1% had parasite clearance by day 3 and 98.6% had parasite clearance by day 7. Of those with temperature readings (n = 140), 129 (92.1%) clinically improved on day 3 and 98.6% improved by day 7. Other indicators of clinical improvement (from day 0 to day 3) included, reported increased level of activity in 136 (97.1%) of the children, and mother's impression of child's improvement in 113 (80.7%). Of the 14 patients not followed to day 28 or to clinical failure, 11 were lost to follow-up by day 7. No allergic skin reactions were noted, and no deaths were observed. These data show that after one year of widespread use of SP in Malawi, Plasmodium falciparum parasite resistance remains very low, and therefore contradicts reports of widespread parasite resistance to SP.

Clinical algorithm for treatment of Plasmodium falciparum malaria in children

BACKGROUND

Identification of children who need antimalarial treatment is difficult in settings where confirmatory laboratory testing is not available, as in much of sub-Saharan Africa. The current national policy in Malawi is to treat all children with fever, usually defined as the mother's report of fever in the child, for presumed malaria. To assess this policy and to find out whether a better clinical case definition could be devised, we studied acutely ill children presenting to two hospital outpatient departments in Malawi.

METHODS

The parent or guardian of each enrolled child (n = 1124) was asked a standard series of questions about the symptoms and duration of the child's illness. Each child was examined, axillary and rectal temperatures and blood haemoglobin concentrations were measured, and a giemsastained thick smear was examined for malaria parasites. Logistic regression procedures were used to identify clinical predictors of parasitaemia.

FINDINGS

High temperature (37.7 degrees C or above), nailbed pallor, enlarged spleen, and being seen at one of the clinics rather than the other were associated with an increased risk of malaria parasitaemia in univariate analyses. A revised malaria case definition of rectal temperature of 37.7 degrees C or higher, splenomegaly, or nailbed pallor was 85% sensitive in identifying parasitaemic children and 41% specific; the corresponding sensitivity and specificity for the nationally recommended definition that equates mother's history of fever with malaria were 93% and 21%. The revised case definition had 89% sensitivity in identifying parasitaemic children with haemoglobin concentration below 80 g/L and 89% sensitivity in identifying children with parasite density greater than 10,000/microL, characteristics that indicate a clear need for antimalarial treatment.

INTERPRETATION

These results suggest that better clinical definitions are feasible, that splenomegaly and pallor are helpful in identifying children with malaria, and that much overtreatment of children without parasitaemia could be avoided.

Antibodies to a Plasmodium falciparum blood-stage antigen as a tool for predicting the protection levels of two malaria-exposed populations

To evaluate the ability of antibodies to Plasmodium falciparum ring-infected erythrocyte surface antigen (Pf155/RESA) epitopes to discriminate between individuals well protected or poorly protected against malaria, a receiver operating characteristic analysis was performed in two populations living in Madagascar and Malawi. The definition of protection was based on longitudinal measurements of clinical malarial attacks during the season of high malaria transmission in the Madagascar study, and on a cross-sectional measurement of parasitemia in the Malawi study. Antibodies to peptides reproducing the 4-mer, 8-mer, and 11-mer of the Pf155/RESA were tested for their reactivities using the Falcon assay screening test-enzyme-linked immunosorbent assay. Maximal detection of poorly protected individuals (specificity = 100%) corresponded to high cutoff antibody titers (range = 1.65-3.0 optical density [OD] units in the Madagascar study and 0.67-1.42 OD units in the Malawi study) and a sensitivity less than 50%. For a given sensitivity of 50%, specificity ranged from 55% to 62% in the Madagascar study, and from 67% to 94% in the Malawi study. The antibody cutoff titers corresponding to minimal misclassification rates ranged from 0.24 to 1.73 OD units in the Madagascar study and from 0.15 to 0.55 OD units in the Malawi study. For each antibody, the highest detectability value as measured by the area under the curve was obtained for anti-R11 in the Malawi study (0.838). In demonstrating such qualities, antibodies to Pf155/RESA epitopes could be used for screening poorly protected populations in which malaria control programs have to be implemented.

Maternal HIV infection and infant mortality in Malawi: evidence for increased mortality due to placental malaria infection

OBJECTIVES

To examine the relationship between maternal HIV infection, placental malaria infection, and infant mortality as a first step in investigating the possibility of increased vertical transmission of HIV due to placental malaria infection.

DESIGN

Retrospective analysis of data from a cohort study of mothers and infants in rural Malawi conducted from 1987 to 1990.

METHODS

Pregnant women in Malawi were enrolled in a study examining chemoprophylaxis during pregnancy. At delivery, placental malaria infection status was determined. Infants born into this study were visited every 2 months for the first 2-3 years of life. Deaths were investigated using a standardized 'verbal autopsy' interview. Maternal serum collected during pregnancy was tested for antibodies to HIV-1 by enzyme-linked immunosorbent assay with Western blot confirmation.

RESULTS

Overall, 138 (5.3%) of 2608 women in the study were HIV-1-seropositive. Infant mortality rates were 144 and 235 per 1000 live births for children born to HIV-seronegative and HIV-seropositive women, respectively (P < 0.001). In a multivariate model, the odds of dying during the post-neonatal period for an infant born to a mother with both placental malaria and HIV infection was 4.5 times greater than an infant born to a mother with only placental malaria, and between 2.7 and 7.7 times greater (depending on birthweight) than an infant born to a mother with only HIV infection.

CONCLUSIONS

This study strongly suggests that exposure to both placental malaria infection and maternal HIV infection increases post-neonatal mortality beyond the independent risk associated with exposure to either maternal HIV or placental malaria infection. If confirmed, malaria chemoprophylaxis during pregnancy could decrease the impact of transmission of HIV from mother to infant.

The use of sputum induction for establishing a diagnosis in patients with suspected pulmonary tuberculosis in Malawi

SETTING

There has been a marked increase in notified cases of smear-negative pulmonary tuberculosis in Malawi since 1986. One reason for this may be related to the difficulties of getting adequate samples of expectorated sputum from patients. Sputum induction with nebulized hypertonic saline may be a simple way of obtaining a better specimen.

OBJECTIVE

To examine the value of sputum induction for detecting cases of smear-positive tuberculosis.

DESIGN

Sputum induction was performed on 82 adults presenting to the Queen Elizabeth Central Hospital, Blantyre, Malawi with clinically suspected pulmonary tuberculosis who were expectorated sputum smear-negative or unproductive of sputum. The induced sputum smear was examined for acid-fast bacilli and cultured for mycobacteria.

RESULTS

Sputum was successfully induced from 73 of the 82 patients (26 previously smear-negative and 47 previously unproductive). The induced sputum was smear-positive in 18 patients (5 previously smear-negative and 13 unproductive). Cultures were positive for Mycobacterium tuberculosis in the 18 smear-positive patients and a further 12 that had been smear-negative. 94 cases of smear-positive pulmonary tuberculosis were notified during the study period. 18 (19%) were as a result of sputum induction.

CONCLUSION

Sputum induction is a useful technique for improving the case detection rate of smear-positive tuberculosis in Malawi.

Antimalarials during pregnancy: a cost-effectiveness analysis

Antenatal clinics (ANC) provide an avenue for interventions that promote maternal and infant health. In areas hyperendemic for Plasmodium falciparum, malaria infection during pregnancy contributes to low birth weight (LBW), which is the greatest risk factor for neonatal mortality. Using current data and costs from studies in Malawi, a decision-analysis model was constructed to predict the number of LBW cases prevented by three antimalarial regimens, in an area with a high prevalence of chloroquine (CQ)-resistant malaria. Factors considered included local costs of antimalarials, number of ANC visits, compliance with dispensed antimalarials, prevalence of placental malaria, and LBW incidence. For a hypothetical cohort of 10,000 women in their first or second pregnancy, a regimen consisting of one dose of sulfadoxine-pyrimethamine (SP) in the second trimester followed by a second dose at the beginning of the third trimester would prevent 205 cases of LBW at a cost of US$ 9.66 per case of LBW prevented. A regimen using a treatment dose of SP followed by CQ 300 mg (base) weekly would prevent 59 cases of LBW at a cost of $62 per case prevented, compared with only 30 cases of LBW prevented at a cost of $113 per case when the regimen involves initial treatment with CQ (25 mg/kg) followed by CQ 300 mg (base) weekly. In areas hyperendemic for CQ-resistant P. falciparum, a two-dose SP regimen is a cost-effective intervention to reduce LBW incidence and it should be included as part of the antenatal care package.

Using clinical signs to diagnose anaemia in African children

Anaemia is a serious and common problem among young children in sub-Saharan Africa. As a first step towards developing guidelines for its recognition and treatment, we conducted a study to evaluate the ability of health workers to use clinical findings to identify children with anaemia. Health care workers examined a total of 1104 children under 5 years of age at two hospital-based outpatient clinics in rural Malawi. Blood samples were taken to determine haemoglobin concentrations. Pallor of the conjunctiva, tongue, palm or nail beds was 66% sensitive and 68% specific in distinguishing children with moderate a anaemia (haemoglobin concentration, 5-8 g/dl) and 93% sensitive and 57% specific in distinguishing those with severe anaemia (haemoglobin concentration, < 5 g/dl). Even without laboratory support, which is often unavailable in rural Africa, clinical findings can identify the majority of children with anaemia.

The efficacy of antimalarial regimens containing sulfadoxine-pyrimethamine and/or chloroquine in preventing peripheral and placental Plasmodium falciparum infection among pregnant women in Malawi

To define an effective and deliverable antimalarial regimen for use during pregnancy, pregnant women at highest risk of malaria (those in their first or second pregnancy) in an area of Malawi with high transmission of chloroquine (CQ)-resistant Plasmodium falciparum were placed on CQ and/or sulfadoxine-pyrimethamine (SP). Of 38 pregnant women who received CQ treatment followed by weekly CQ prophylaxis (CQ/CQ) for at least 45 days prior to delivery, 32% had placental malaria infection, compared with 26% of 50 pregnant women who received a treatment dose of SP followed by weekly CQ prophylaxis (SP/CQ), and only 9% of 71 pregnant women who received a two-dose SP regimen (SP/SP; given once during the second trimester and repeated at the beginning of the third trimester) (P = 0.006, by chi-square test). During the peak transmission season from April to July, 47% of the women who received CQ/CQ had placental malaria infection at delivery, as compared with 37% of the women who received SP/CQ, and 10% of women who received SP/SP (P = 0.004, by chi-square test). Among women in their first or second pregnancy, two treatment doses of SP were highly effective in decreasing the proportion of women with placental malaria infection at delivery.

In-hospital morbidity and mortality due to malaria-associated severe anaemia in two areas of Malawi with different patterns of malaria infection

We examined the relative contribution of malaria-associated severe anaemia (parasitaemia and haematocrit < or = 15%) to malaria-related morbidity and mortality among children admitted at 2 hospitals in areas with different seasonal patterns of malaria infection in Malawi. The prevalence of malaria-associated severe anaemia was 8.5% among admissions at the hospital in an area with sustained, year-round infection (Mangochi District Hospital [MDH]), compared to 5.2% at the hospital in an area with a fluctuating pattern of infection (Queen Elizabeth Central Hospital [QECH]). Infants at MDH were nearly twice as likely to have malaria-associated severe anaemia as were those at QECH. Parasite density on admission was not related to the risk of severe anaemia at MDH, but it was at QECH. A similar proportion of all deaths was attributed to malaria at MDH (17.5%) and QECH (20.4%). However, malaria-associated severe anaemia accounted for 54% of malaria-related deaths at MDH compared to only 32% at QECH. Malaria-associated severe anaemia contributed significantly to morbidity and mortality at both sites, but its impact was more marked in the area with a sustained pattern of infection. These findings suggest that seasonal fluctuations in malaria infection may contribute to differences in patterns of malaria disease.

HIV-1 infection among women of reproductive age in a rural district in Malawi

OBJECTIVES

To determine HIV-1 seroprevalence in pregnant women attending antenatal clinics in a rural district in Malawi, and to estimate the rate of HIV-1 infection in the district among women of reproductive age.

DESIGN AND SETTING

Cross-sectional survey conducted from 1987 to 1990 of women enrolled at antenatal clinics at four sites (two towns and two villages).

METHODS

Questionnaires were administered and sera screened at delivery. Population infection estimates were based on national census and survey data.

RESULTS

Of 3953 pregnant women tested, 283 (7.2%) were HIV-1-seropositive. Women enrolled at town sites were significantly more likely to be HIV-1-infected than village women (11.3 versus 3.9%; P < 0.001). Higher infection rates were associated with age 20-29 years, first or second pregnancy, increased education or socioeconomic status, and living within 8 km of the clinic. It was estimated that over 7300 women of reproductive age were HIV-1-infected in this rural district.

CONCLUSIONS

Seroprevalence rates in pregnant women in rural towns were intermediate between rates in villages and previously documented rates in cities in Malawi. Although village sites had lower seroprevalence rates, they accounted for over half the estimated HIV-1 infection in childbearing women in this district.

Antibodies to ring-infected erythrocyte surface antigen (Pf155/RESA) protect against P. falciparum parasitemia in highly exposed multigravidas women in Malawi

To determine whether antibodies to defined B-cell epitopes of Plasmodium falciparum antigens were related to protection against parasitemic attacks in highly exposed pregnant women, two samples of 235 with no initial P. falciparum parasitemia (NP) and 89 multigravidas who presented initial P. falciparum parasitemia (IP) were enrolled in an antimalarial prophylaxis trial in the Mangochi District in Malawi. Sera were collected under effective prophylaxis and tested for antibody measurement using FAST-ELISA. Mean antibody titers to synthetic peptides reproducing the 3 major B-cell epitopes of the ring-infected erythrocyte surface antigen (Pf155/RESA), as (EENV)4, (EENVEHDA)4 and (DDEHVEEPTVA)3, were higher in the NP than in the IP multigravidas, and this remained consistent within the season of malaria transmission (all p < 0.05). All antibodies to Pf155/RESA were positively intercorrelated within each group. Mean antibody titers to peptide (PNAN)5 reproducing the major B-cell epitope of the circumsporozoite protein (CS protein) were similar between NP and IP multigravidas in both dry and rainy season. Antibodies to Pf155/RESA epitopes may contribute to immune protection against blood-stage parasite multiplication in these highly malaria-exposed pregnant women.

Risk factors for anemia in young children in rural Malawi

Anemia is an increasingly recognized health problem in African children. To determine the prevalence of and risk factors for anemia in young children, we enrolled 252 pregnant women and studied their newborn infants in Mangochi District in southern Malawi. At the first follow-up visit after birth at approximately two months of age, the mean hematocrit value of the 252 infants was 29.5%, and 64 infants (25%) were anemic (hematocrit value < 25%). Placental malaria infection was the strongest risk factor for an infant having anemia at the first follow-up (relative risk = 2.0, P = 0.003). Infants who had Plasmodium falciparum parasitemia at the first follow-up had lower hematocrit values than infants without parasitemia (median 28% versus 31%; P = 0.02). Neither the mother's hematocrit at enrollment, her hematocrit at delivery, sex of the infant, nor fever illness in the infant was associated with having a hematocrit less than 25% at the first follow-up. Although infants with hematocrit values less than 25% were more likely than infants with higher hematocrit values to die during the first year of life, this difference was not statically significant (relative risk = 1.7, P = 0.15). In rural Malawi, anemia commonly affects young infants, is acquired early in life, and is probably a risk factor for death in infancy. Strategies to reduce anemia in infants must address P. falciparum infection, both during pregnancy and in the first few months of life.

Circulating plasma receptors for tumour necrosis factor in Malawian children with severe falciparum malaria

Tumour necrosis factor (TNF) concentrations are increased in the plasma during a malarial illness, and are highest in patients with severe or fatal disease. We have studied the plasma concentrations of two soluble receptors (sTNF-R1 and sTNF-R2), which act as binding proteins for TNF, in children with falciparum malaria. In 52 Malawian children with malaria, plasma concentrations of both sTNF-R1 (mean (S.D.) 4759(2552) pg/ml) and sTNF-R2 (59077(37102) pg/ml) were greatly increased when compared with levels of convalescence (sTNF-R1 718(68), and sTNF-R2 8015(7021) pg/ml), and in controls without malaria (486(1353) and 4380(2168)). Concentrations of both receptors correlated with plasma levels of TNF measured by immunoradiometric assay, but not with those of another cytokine, IL-6. The mean plasma concentrations of both immunoreactive TNF and soluble TNF receptors were greater in patients with cerebral malaria than those with uncomplicated malaria. Despite high levels of immunoreactive TNF in the plasma of patients acutely ill with malaria, no bioactive TNF could be detected in these patients by the WEHI cell bioassay. Soluble TNF receptors are present in greatly increased concentrations in the plasma of patients with malaria and may play a role in mediating or modulating the pathogenetic effects of the cytokine.

Immunoglobulin complex deposits in Plasmodium falciparum-infected placentas from Malawi and Papua New Guinea

Term placentas from 35 patients infected with Plasmodium falciparum were obtained in Malawi in southeast Africa and six term placentas from patients infected with P. falciparum were obtained in Wewak, Papua New Guinea, Melanesia. The placental tissues were examined by light microscopy and by an immunohistologic method to compare the pathologic changes of placentas in the two malaria-endemic countries. Using the number of parasitized red blood cells (PRBC) in intervillous spaces, pregnant women from Malawi with placental parasitemia were categorized into three groups. In the high PRBC group (> 20%, group I), there was no deposition of IgE in fetal blood vessels. In contrast, IgE was observed in fetal blood vessels of the intermediate PRBC group (1-10%, group II) and low PRBC group (< 1%, group III). In all six placentas from Papua New Guinean women, deposition of immune complexes, including IgE, was observed in the fetal blood vessels. All placentas with deposition of IgE in fetal blood vessels showed no sequestration of malaria parasites in intervillous spaces. Our data indicate that the amount of deposition of IgE in the placenta from women infected with P. falciparum is inversely correlated with the degree of parasitemia at that site.

Rapid coma resolution with artemether in Malawian children with cerebral malaria

Artemisinin compounds clear parasitaemia more rapidly than other drugs do in both mild and severe malaria, but no advantage in clinical efficacy has been shown. We have compared artemether treatment with standard quinine treatment in Malawian children with cerebral malaria. 65 unconscious children were randomly allocated to intravenous quinine (n = 37) or intramuscular artemether (n = 28) treatment. The two groups were well matched for various prognostic features. Median parasite clearance times were shorter in the artemether group (28 [interquartile range 18-34] vs 40 [36-44] h in the quinine group, p = 0.0002). Coma resolution times were also shorter with artemether than with quinine (8 [4-15] vs 14 [10-36] h, p = 0.01).

Malaria chemoprophylaxis compliance in pregnant women: a cost-effectiveness analysis of alternative interventions

Compliance to malaria chemoprophylaxis among pregnant women in Malaŵi has historically been low. Three separate interventions, based upon an ethnographic study of malaria beliefs among pregnant women in Malaŵi, were introduced to increase compliance to the malaria chemoprophylaxis program provided by the Ministry of Health. Each intervention consisted of a health education message and an antimalarial drug. A cost-effectiveness analysis of the interventions was conducted to compare the interventions as alternative strategies to increase compliance among pregnant women.

Intravenous immunoglobulin in the treatment of paediatric cerebral malaria

Hyperimmune globulin can inhibit and reverse the cytoadherence between Plasmodium falciparum-infected erythrocytes and melanoma cells in vitro. Cytoadherence is believed to mediate disease in cerebral malaria. Therefore we studied the efficacy of i.v. immunoglobulin, purified from the plasma of local semi-immune blood donors, as an adjunct to standard treatment for cerebral malaria in Malawian children. The immunoglobulin preparation (IFAT antimalarial antibody titre 1:5120) recognized erythrocyte-associated antigens of each of 22 Malawian P. falciparum isolates studied, and reversed binding of Malawian isolates to melanoma cells. Immunoglobulin did not reverse binding to human monocytes or to cells of the human histiocytic lymphoma cell line U937. Thirty-one children with P. falciparum parasitaemia and unrousable coma were enrolled. All were treated with i.v. quinine dihydrochloride; in addition patients were randomized to receive either immunoglobulin (400 mg/kg by i.v. infusion over 3 h) or placebo (albumen and sucrose by similar infusion) in a double blind trial with sequential analysis. Of 16 patients receiving immunoglobulin, five (31%) died and five survivors had neurological sequelae. Of 15 patients receiving placebo, one (7%) died and two had sequelae. Parasite clearance, fever clearance and coma resolution times in survivors were similar in the two groups. Although the difference in outcome between the two groups was not significant, the trial was stopped because immunoglobulin was demonstrated not to be superior to placebo.

Helicobacter pyrlori in Malawi, central Africa

A total of 160 adult Malawians with epigastric pain for longer than 2 weeks was investigated by endoscopy and serologically for evidence of infection with Helicobacter pylori. The organism was demonstrated histologically and/or by culture in 141 (88%) patients. With histological means and/or culture as the 'gold standard', the histological technique was 100% sensitive while culture was only 81% sensitive. All isolates tested were sensitive to amoxycillin and tetracycline; 74% were resistant to metronidazole. Endoscopic findings were normal in 104 (65%) patients (86.5% H. pylori positive). Evidence of duodenal ulcer was found in 41 (25%) patients (95% H. pylori positive). Histologically, gastritis was common, severe gastritis being associated with increased colonisation by H. pylori. Two kinds of urease test were found to be 100% specific for the presence of H. pylori. The sensitivity of the serological test (Helico-G test) was 98% but its specificity was only 27%. These results provide important background information for planned therapeutic studies in patients with upper gastro-intestinal disease in Malawi.

Extensive genetic diversity in the HLA class II region of Africans, with a focally predominant allele, DRB1*1304

Molecular HLA class II typing of greater than 1700 individuals from The Gambia in West Africa and Malawi in South-Central Africa revealed a striking diversity of HLA DRB-DQB haplotypes as defined by restriction fragment length polymorphism (RFLP); this diversity is twice as extensive as that found in northern Europeans. Despite this diversity, sequence and PCR/oligonucleotide analysis showed that the recently described variant DRB1*1304 is the commonest DRB1 allele in The Gambia. The sequence, geographical distribution, and RFLP association of this allele, together with homozygosity test results, suggest that DRB1*1304 may have arisen from DRB1*1102 and have reached its remarkably high frequency as a result of recent directional selection. The prevalence of this unusual allele has implications for trials of subunit vaccines in this area. The extensive and distinctive HLA class II region polymorphism in sub-Saharan Africans is consistent with evidence from other genetic loci implying an African origin of modern Homo sapiens.

Effect of Plasmodium falciparum malaria infection on the plasma concentration of alpha 1-acid glycoprotein and the binding of quinine in Malawian children

1. We have measured plasma concentrations of alpha 1-acid glycoprotein (AGP) in 18 healthy children and 85 children with falciparum malaria in Malawi. In addition, we determined the degree of protein binding of quinine (QN) in the plasma of 52 of the patients and each of the healthy controls. 2. The mean plasma AGP concentration was higher in patients than in controls (P less than 0.0001) and remained elevated 3 weeks after complete resolution of malaria infection. 3. The mean unbound QN fraction was significantly less (P less than 0.00001) in patients with malaria (0.128 +/- 0.037) than in controls (0.193 +/- 0.051) and significantly higher (P = 0.02) in convalescence (0.153 +/- 0.067) than during acute illness. 4. There were highly significant negative correlations between plasma AGP concentration and the free QN fraction in spiked plasma samples (r = -0.534, P less than 0.0001, n = 93) and in clinical samples (r = -0.484, P less than 0.00001, n = 225). There was a significant positive correlation between plasma concentrations of AGP and another acute phase reactant, C reactive protein (P less than 0.001).

Efficacy of quinine for falciparum malaria according to previous chloroquine exposure

Chloroquine has been reported to antagonise the anti-parasitic action of quinine against Plasmodium falciparum in vitro. We looked for evidence of any such antagonism in vivo. In 123 Malawian children with cerebral malaria treated with parenteral quinine, the likelihood of survival and the rate of recovery were much the same in patients who had taken chloroquine and those who had not. In these circumstances we found no evidence of chloroquine/quinine antagonism.

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.