Antenatal rubella serosurvey in Maputo, Mozambique.
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OBJECTIVE: To describe the epidemiology of rubella in Mozambique. METHODS: Cross-sectional serosurvey of rubella IgG antibodies among women attending antenatal clinics in Maputo in February-April 2002 to assess the prevalence and titres. RESULTS: Rubella IgG antibodies were detected in 95.3% (95% confidence interval 94.0%-96.6%) of 974 pregnant women. Age and residence did not significantly affect the prevalence of rubella IgG antibodies. However, the mean titre of rubella IgG antibodies was higher in women <20 years of age than in women > or =30 years of age (P < 0.01), and women living in urban areas had higher antibody titres than those living in suburban areas (P < 0.0001). CONCLUSIONS: The seroprevalence of rubella IgG antibodies among pregnant women in Maputo is high. Whether this is due to recent exposure to wild rubella virus or to exposure to rubella virus earlier in life is unclear. Studies on the burden of congenital rubella syndrome could address this matter. (+info)
Relationship between haemoglobin and haematocrit in the definition of anaemia.
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INTRODUCTION: Anaemia is the most frequent haematological disorder in childhood. The notion that defines naemia does not change throughout life, although parameters used for its evaluation show significant variations during childhood. Haematocrit (Hct) (%) is usually defined as three times the value of haemoglobin (Hgb) (g/dl), while the clinical definition of anaemia is related to either an abnormal Hct or Hgb value. OBJECTIVE: To evaluate the agreement between Hgb and Hct values in the definition of anaemia, the relationship between these two parameters and their age-dependence. METHODS: The Hct and Hgb paired values from children aged 2-18 months from Ifakara (Tanzania) and children aged 1-4 years from Manhica (Mozambique) were analysed. Haematological determinations of the Manhica samples were done using a KX-21N cell counter (Kobe, Japan) and Ifakara samples were analysed in a semiautomatic cell counter (Sysmex F800 microcell counter, TOA Medical Electronics, Kobe, Japan). The kappa-statistic was used to calculate the agreement between anaemia definitions in each group. Crude and multivariate relationship between Hct and Hgb levels were analysed by linear regression model estimation. The age-dependence of the crude ratio (Hct/Hgb) was analysed using linear regression models and fractional polynomials. RESULTS: The prevalences of mild and moderate anaemia as defined by Hgb levels in the Manhica group were 61% and 6%, respectively, and 41% and 2% by Hct. In the Ifakara group these were 74% and 10%, respectively, by Hgb and 42% and 3% by Hct, respectively. Agreement between mild and moderate anaemia definitions made up from Hgb or from Hct levels were from fair to moderate. Hct levels decreased with age for high Hgb levels, whereas they increased for low Hgb levels. The classification of cases is improved when higher age-related cut-off values for Hct are used. The crude relationship between Hct and Hgb levels was significantly different from 3, and this was modified by age. The evaluation of the age-dependence ratio (Hct/Hgb) showed a non-linear relationship with an asymptotic trend to 3. CONCLUSIONS: Measurement of haematocrit count is easy and can be performed in most rural health care centres. However, the corresponding Hgb levels cannot be derived with an acceptable accuracy using the value 3 as a conversion factor. Furthermore, the commonly assumed 'equivalent' cut-off points for anaemia definitions need to be re-evaluated. (+info)
Clinical and laboratorial evaluation of urinary schistosomiasis in Brazilians after staying in Mozambique.
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We examined 87 Brazilian individuals of a group of 132 that, on July and November 1994, participated in a peace mission in Mozambique. They served in an endemic area for haematobic schistosomiasis, where they swam in Licungo river during leisure time. Their arithmetic mean age was 31 year and all of them were male. Their urine test showed that 30 (34.5%) eliminated S. haematobium eggs and 55 (63.2%) presented positive serology by the enzyme-linked immunoelectrotransfer blot test with purified microsomal antigen of S. haematobium adult worms. Eosinophilia was found in 30 (34.5%), haematuria in 26 (29.9%), dysuria in 32 (36.8%) and lumbar pain in 36 (41.4%). All of those that eliminated eggs through urine had positive serology. Among the 25 patients with positive serology and without S. haematobium eggs in the urine test, 13 were symptomatic and 12 asymptomatic. The treatment with praziquantel for the 30 patients, with urine positive to S. haematobium eggs, presented 70% of parasitological cure. (+info)
Invasive pneumococcal disease in children<5 years of age in rural Mozambique.
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OBJECTIVES: To estimate the incidence and epidemiological characteristics of invasive pneumococcal disease (IPD) in children<5 years of age living in a rural area of southern Mozambique. METHODS: As part of the clinical management of children admitted to Manhica District Hospital, prospective surveillance for invasive bacterial disease was conducted from June 2001 to May 2003. The level of antibiotic resistance of the isolates was also analysed. RESULTS: Pneumococcus was the most commonly isolated bacterium, accounting for 212 episodes. The estimated crude incidence rate of IPD in the study area among children<5 years of age was 416/100,000 per child-year at risk. The youngest age group (<3 months) had the highest incidence (779/100,000). Cases were detected during both rainy and dry seasons. The most common clinical diagnosis was pneumonia, made in 146/212 (69%) of the episodes of IPD. The overall case fatality rate was 10%, being highest among children with pneumococcal meningitis (5/9=56%). Pneumococcal isolates were highly susceptible to penicillin (86% susceptible and 14% with intermediate resistance) and chloramphenicol (98% susceptible). In contrast, up to 37% of the isolates tested were non-susceptible to cotrimoxazole. CONCLUSIONS: Incidence rates of IPD and associated mortality shown in this study highlight the need for pneumococcal vaccines in rural Africa, which must be effective in infants and young children. (+info)
Modeling a field trial of the RTS,S/AS02A malaria vaccine.
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A double-blind, phase IIb, randomized controlled trial of the malaria vaccine RTS,S/AS02A showed an efficacy of 45.0% in reducing the force of infection for Plasmodium falciparum and of 29.9% in reducing incidence of clinical malaria in children 1-4 years of age in Manhica, Mozambique. We simulate this trial using a stochastic model of P. falciparum epidemiology, and the setting-specific seasonal pattern of entomologic inoculations as input. The simulated incidence curve for the control group was comparable with that observed in the trial. To reproduce the observed efficacy in extending time to first infection, the model needed to assume an efficacy of 52% in reducing the force of infection. This bias arises as a result of acquired partial immunity against blood stages, thus suggesting an explanation for the lower efficacy observed in a previous trial in semi-immune adult men in The Gambia. The shape of the incidence of infection curve for the vaccine cohort in Manhica indicates that the vaccine provides incomplete protection to a large proportion of the vaccinees, rather than offering complete protection to some recipients and none to others. This behavior is compatible with a model of no decay in efficacy over the six-month surveillance period of the trial. The model accurately reproduced the lower efficacy against clinical disease than against infection. In the simulations this finding resulted from loss of acquired clinical immunity as a result of a reduction in the force of infection in the vaccinated cohort. The model also predicted greater efficacy against severe diseases than against clinical disease. The success of the simulation model in reproducing the results of the Manhica trial encourages us to apply the same model to predict the potential public health and economic impact if RTS,S/AS02A were to be introduced into the existing expanded program on immunization. (+info)
Community response to intermittent preventive treatment delivered to infants (IPTi) through the EPI system in Manhica, Mozambique.
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OBJECTIVE: To describe attitudes to the expanded programme on immunization (EPI) and intermittent preventive treatment in infants (IPTi), and perceptions of the relationship between them. In particular, whether the introduction of IPTi negatively affects community attitudes to, or use of, EPI; or, conversely, whether and if so how, the concurrent delivery of IPTi and immunization influences perceptions of IPTi. METHODS: Anthropological study carried out in the context of a trial of IPTi with sulphadoxine-pyrimethamine delivered alongside routine EPI vaccinations. We used open in-depth interviews, semi-structured interviews and participant observation, conducted in both community and clinic settings. RESULTS: IPTi was generally acceptable, in spite of initial resistance. Perceived negative aspects of IPTi did not affect perceptions of EPI, and IPTi was not misinterpreted as immunization against malaria, leading to a reduction of other preventive measures or delay in treatment seeking. Initial resistance was related more to the trial than to IPTi per se, but both rejection and acceptance were embedded in a complex constellation of local and wider contextual factors. CONCLUSIONS: IPTi delivered together with EPI was generally accepted after initial rejection. The factors that led to this rejection were largely local and trial related, but they did resonate with much wider cultural themes (rumours about research and health interventions, gender inequality and health-related decision making). The prior acceptance and routine administration of EPI played a key role in the acceptance of IPTi in this community. However, more studies, in different social and cultural settings and using different drugs and regimens, are needed before generalizations can be made. Although trial settings are different from actual implementation, it is necessary to study acceptability before implementation in order to anticipate problems and design information campaigns to ensure maximum community acceptance. (+info)
Haematological and biochemical indices in young African children: in search of reference intervals.
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INTRODUCTION: The reference intervals of haematological and biochemical indices currently used in Africa are derived from data collected from populations living in industrialized countries. Few studies have been performed in Africa questioning the validity of these values when applied to local African populations. OBJECTIVE: To provide reference intervals of haematological [haemoglobin (Hb), white blood cells (WBC), haematocrit (Htc) and platelets] and biochemical indices (ALT, creatinine and bilirubin) for children aged 1-4 from a rural area of southern Mozambique. METHODS: Reference intervals were developed using the 2.5 and 97.5 centiles. Partition tests were performed to evaluate age and gender differences. Quantile regression models were estimated for those variables in which age partition was recommended. Deviances from linearity in the estimated models were evaluated using fractional polynomials of first or second degree. Agreement to classify normality, using the estimated reference intervals or values in use in a western paediatric hospital, was made using the kappa statistic. RESULTS: Reference intervals for Hb, WBC, Htc, platelets, ALT and creatinine show significant differences by age. Gender differences were observed for creatinine values, while for bilirubin there were no significant differences for age or gender. Estimated Hb and Htc reference intervals in African children were lower than the accepted western ones, while ALT values were higher in the former. Agreement between normal classification, using the estimated intervals or the western values, was from slight to fair. CONCLUSIONS: Reference intervals of haematological and biochemical indices based on results from western individuals of the same age are not in agreement with the estimated values for African children. These observed values should not be used as a rule to define normality, but are the ones usually found in this population where anaemia, malaria and high mortality rates are also common. (+info)
Levels and trends of demographic indices in southern rural Mozambique: evidence from demographic surveillance in Manhica district.
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BACKGROUND: In Mozambique most of demographic data are obtained using census or sample survey including indirect estimations. A method of collecting longitudinal demographic data was introduced in southern Mozambique since 1996 (DSS -Demographic Surveillance System in Manhica district, Maputo province), but the extent to which it yields demographic measures that are typical of southern rural Mozambique has not been evaluated yet. METHODS: Data from the DSS were used to estimate the levels and trends of fertility, mortality and migration in Manhica, between 1998 and 2005. The estimates from Manhica were compared with estimates from Maputo province using the 1997 National census and 1997 Demographic and Health Survey (DHS). The DHS data were used to estimate levels and trends of adult mortality using the siblings' histories and the orphanhood methods. RESULTS: The populations in Manhica and in Maputo province are young (44% <15 years in Manhica and 42% in Maputo); with reduced adult males when compared to females (all ages sex ratio of 78.7 in Manhica and 89 in Maputo). Fertility in Manhica is at a similar level as in Maputo province and has remained around 5 children per woman, during the eight years of surveillance in Manhica. Although the infant mortality rate (IMR) in Mozambique has decreased during the last two decades (from 148 deaths per 1000 live births in 1980 to 101 in 2003), it has remained stable around 80 in Manhica during the surveillance period. Adult mortality has increased both in Manhica (probability of dying from ages 15 to 60 increased from 0.4 in 1998 to 0.6 in 2005 in Manhica, from 0.3 in 1992 to 0.4 in 1997 in Maputo province and from 0.1 in 1980 to 0.6 in 2000 in Mozambique). Consequently, the life expectancy decreased from 53 to 46 in Manhica and from 42 years in 1997 to 38 in 2004 in Mozambique. Migration is high in Manhica but tends to stabilise after the movements of resettlement that followed the end of the civil war in 1992. CONCLUSION: The population under demographic surveillance in Manhica district presents characteristics that are typical of southern rural Mozambique, with predominance of young people and reduction of adult males. Labour migration and excess adult male mortality are the major factors for the reduction of adult males. Mortality is high and only infant mortality has started to stabilise while adult mortality has increased, and as consequence, life expectancy has decreased. The Manhica DSS is an adequate tool to report demographic measures for southern rural Mozambique. (+info)