The Changing Epidemiology of Malaria in Ifakara Town, Southern Tanzania.

Between 1995 and 2000 there were marked changes in the epidemiology of malaria in Ifakara, southern Tanzania. We documented these changes using parasitological and clinical data from a series of community- and hospital-based studies involving children up to the age of 5 years. There was a right shift and lowering in the age-specific parasite prevalence in the community-based cohort studies. The incidence of clinical malaria in placebo-receiving infants in additional study cohorts dropped from 0.8 in 1995 to 0.43 episodes per infant per year in 2000, an incidence rate ratio of 0.53 (95% confidence interval: 0.404, 0.70, P<0.0001). At the same time, there was an increase in the total number of malaria admissions and a marked right shift in the age pattern of these admissions (median age in 1995 1.55 years vs. 2.33 in 2000, P<0.0001). However, the burden of malaria deaths remained in infants. We discuss how these dramatic changes in the epidemiology of malaria may have arisen from the use of currently available malaria control tools. Caution is required in the interpretation of hospital-based data as it is likely to underestimate the impact of anaemia on mortality in the community, where most paediatric deaths occur. Even in low/moderate malaria transmission settings, where older children suffer most malaria episodes, targeting effective malaria control at infants may produce important reductions in infant mortality caused by malaria

Varying efficacy of intermittent preventive treatment for malaria in infants in two similar trials: public health implications.

BACKGROUND\ud \ud Intermittent preventive treatment (IPTi) with sulphadoxine-pyrimethamine (SP) in infants resulted in different estimates of clinical malaria protection in two trials that used the same protocol in Ifakara, Tanzania, and Manhiça, Mozambique. Understanding the reasons for the discrepant results will help to elucidate the action mechanism of this intervention, which is essential for rational policy formulation.\ud \ud METHODS\ud \ud A comparative analysis of two IPTi trials that used the same study design, follow-up, intervention, procedures and assessment of outcomes, in Tanzania and Mozambique was undertaken. Children were randomised to receive either SP or placebo administered 3 times alongside routine vaccinations delivered through the Expanded Program on Immunisation (EPI). Characteristics of the two areas and efficacy on clinical malaria after each dose were compared.\ud \ud RESULTS\ud \ud The most relevant difference was in ITN's use ; 68% in Ifakara and zero in Manhiça. In Ifakara, IPTi was associated with a 53% (95% CI 14.0; 74.1) reduction in the risk of clinical malaria between the second and the third dose; during the same period there was no significant effect in Manhiça. Similarly, protection against malaria episodes was maintained in Ifakara during 6 months after dose 3, but no effect of IPTi was observed in Manhiça.\ud \ud CONCLUSION\ud \ud The high ITN coverage in Ifakara is the most likely explanation for the difference in IPTi efficacy on clinical malaria. Combination of IPTi and ITNs may be the most cost-effective tool for malaria control currently available, and needs to be explored in current and future studies.\ud \ud TRIAL REGISTRATION\ud \ud Manhiça study registration number: NCT00209795Ifakara study registration number: NCT88523834

A randomized comparison of two anemia treatment regimens in Tanzanian children.

We used a prospective, open-label randomized trial to evaluate two treatment regimens in Tanzanian children two months to four years of age presenting to a hospital with a packed cell volume (PCV) < 25%. Treatment was either standard (14 days of ferrous sulfate and an antimalarial) or extended (three months of ferrous sulfate and three antimalarial treatments). The prevalence of anemia was measured two weeks after completion of treatment and six months after recruitment. Two weeks after completing treatment, the prevalence of PCV < 33% was 58% in the standard treatment arm and 44% in the extended treatment group (P = 0.04), and the mean PCV was significantly higher in the extended treatment arm (32.1%, SD = 4.5% versus 30.8%, SD = 4.9%; P = 0.031). However, there was no difference in the prevalence of PCV < 25% in the first survey, and the benefits of extended therapy were only apparent six months after recruitment in children compliant with the extended treatment (odds ratio of PCV < 25% = 0.16, P = 0.06). Compliance was satisfactory in only 39% (82 of 209) of the children in the first week of treatment. Extending the duration of therapy and improving compliance may have health benefits for anemic children in malaria-endemic settings

Age interactions in the development of naturally acquired immunity to Plasmodium falciparum and its clinical presentation

Background Naturally acquired malaria immunity has many determinants and, in the absence of immunological markers of protection, studies assessing malaria incidence through clinical endpoints remain an approach to defining immunity acquisition. We investigated the role of age in disease incidence and the effects of chemoprophylaxis on clinical immunity development to Plasmodium falciparum during a randomised controlled trial. Methods and Findings A total of 415 Tanzanian infants were randomly assigned to receive weekly malaria prophylaxis with Deltaprim (3.125 mg of pyrimethamine plus 25 mg of dapsone) or placebo between the ages of 2 and 12 mo. Children were followed up until 4 y of age. Uncomplicated febrile malaria, severe malaria, and anaemia morbidity were assessed through hospital-based passive surveillance. Compared with the group of control participants, there was a marked reduction in the incidence of clinical malaria, severe malaria, and anaemia in the group of children who had received chemoprophylaxis during the first year of life. After discontinuing the intervention, there was a significant increase in the incidence of clinical malaria for 2 y. The cumulative rates of clinical malaria, by age 4 y, were slightly higher in the group of children who had previously received chemoprophylaxis: 3.22 episodes versus 3.02 episodes in the group of control participants; rate difference 0.20 (95% confidence interval [CI]: −0.21 to 0.59). By age 4 y, the cumulative rates of severe malaria, however, were slightly lower in chemosuppressed children (0.47 versus 0.59) (rate difference −0.12 [95% CI: −0.27 to 0.03]). The number of episodes of anaemia was also slightly lower in chemosuppressed children by age 4y: 0.93 episodes (95% CI: 0.79 to 0.97) versus 1.12 episodes in the group of control participants (95% CI: 0.97 to 1.28) (rate difference −0.19 [95% CI: −0.40 to 0.01]), respectively. Conclusions Reducing exposure to P. falciparum antigens through chemoprophylaxis early in life can delay immunity acquisition. Infants appear to acquire immunity faster than older children, but have a higher risk of developing severe forms of malaria and anaemia. These findings provide insight on the interplay between immunity and exposure-reduction interventions

Risk factors for presentation to hospital with severe anaemia in Tanzanian children: a case-control study.

In malaria endemic areas anaemia is a usually silent condition that nevertheless places a considerable burden on health services. Cases of severe anaemia often require hospitalization and blood transfusions. The objective of this study was to assess risk factors for admission with anaemia to facilitate the design of anaemia control programmes. We conducted a prospective case-control study of children aged 2-59 months admitted to a district hospital in southern Tanzania. There were 216 cases of severe anaemia [packed cell volume (PCV) < 25%] and 234 age-matched controls (PCV > or = 25%). Most cases [55.6% (n = 120)] were < 1 year of age. Anaemia was significantly associated with the educational level of parents, type of accommodation, health-seeking behaviour, the child's nutritional status and recent and current medical history. Of these, the single most important factor was Plasmodium falciparum parasitaemia [OR 4.3, 95% confidence interval (CI) 2.9-6.5, P < 0.001]. Multivariate analysis showed that increased recent health expenditure [OR 2.2 (95% CI 1.3-3.9), P = 0.005], malnutrition [OR 2.4 (95%CI 1.3-4.3), P < 0.001], living > 10 km from the hospital [OR 3.0 (95% CI 1.9-4.9), P < 0.001], a history of previous blood transfusion [OR 3.8 (95% CI 1.7-9.1), P < 0.001] and P. falciparum parasitaemia [OR 9.5 (95% CI 4.3-21.3), P < 0.001] were independently related to risk of being admitted with anaemia. These findings are considered in terms of the pathophysiological pathway leading to anaemia. The concentration of anaemia in infants and problems of access to health services and adequate case management underline the need for targeted preventive strategies for anaemia control

Paediatric referrals in rural Tanzania: the Kilombero District Study – a case series

BACKGROUND: Referral is a critical part of appropriate primary care and of the Integrated Management of Childhood Illness (IMCI) strategy. We set out to study referrals from the aspect both of primary level facilities and the referral hospital in Kilombero District, southern Tanzania. Through record review and a separate prospective study we estimate referral rates, report on delays in reaching referral care and summarise the appropriateness of pediatric referral cases in terms of admission to the pediatric ward at a district hospital METHODS: A sample of patient records from primary level government health facilities throughout 1993 were summarised by age, diagnosis, whether a new case or a reattendance, and whether or not they were referred. From August 1994 to July 1995, mothers or carers of all sick children less than five years old attending the Maternal and Child Health (MCH) clinic or outpatient department (OPD) of SFDDH were interviewed using a standard questionnaire recording age, sex, diagnosis, place of residence, whether the child was admitted to the paediatric ward, and whether the child was referred. RESULTS: From record review, only 0.6% of children from primary level government facilities were referred to a higher level of care. At the referral hospital, 7.8 cases per thousand under five catchment population had been referred annually. The hospital MCH clinic and OPD were generally used by children who lived nearby: 91% (n = 7,166) of sick children and 75% (n = 607) of admissions came from within 10 km. Of 235 referred children, the majority (62%) had come from dispensaries. Almost half of the referrals (48%) took 2 or more days to arrive at the hospital. Severe malaria and anaemia were the leading diagnoses in referred children, together accounting for a total of 70% of all the referrals. Most referred children (167/235, 71%) were admitted to the hospital paediatric ward. CONCLUSIONS: The high admission rate among referrals suggests that the decision to refer is generally appropriate, but the low referral rate suggests that too few children are referred. Our findings suggest that the IMCI strategy may need to be adapted in sparsely-populated areas with limited transport, so that more children may be managed at peripheral level and fewer children need referral

Duration of Protection and Age-Dependence of the Effects of the SPf66 Malaria Vaccine in African Children Exposed to Intense Transmission of Plasmodium falciparum

The SPf66 synthetic vaccine is safe and partly efficacious against Plasmodium falciparum malaria among children 1-5 years old. The estimated vaccine efficacy [VE] for all clinical episodes over a period of 18 months after the third dose is 25% (95% confidence interval [CI], 1%-44%; P = .044). The observed temporal variations in efficacy could have been due to chance (likelihood ratio χ2 = 13.8,8 df; P = .086). Efficacy against clinical malaria did not vary significantly with age χ2 = 1.07, 4 df; P = .90). Overall parasite density was 21% lower in vaccine recipients than in the placebo group (95% CI, 0%-38%; P = .044). Further development of SPf66 may require trials to evaluate safety, immunogenicity, and efficacy when administered in the first year of life, together with other vaccines contained in the Expanded Programme of Tmmunization schedul

Mobilisation of critically ill patients receiving norepinephrine: a retrospective cohort study

Background: Mobilisation and exercise intervention in general are safe and feasible in critically ill patients. For patients requiring catecholamines, however, doses of norepinephrine safe for mobilisation in the intensive care unit (ICU) are not defined. This study aimed to describe mobilisation practice in our hospital and identify doses of norepinephrine that allowed a safe mobilisation. Methods: We conducted a retrospective single-centre cohort study of 16 ICUs at a university hospital in Germany with patients admitted between March 2018 and November 2021. Data were collected from our patient data management system. We analysed the effect of norepinephrine on level (ICU Mobility Scale) and frequency (units per day) of mobilisation, early mobilisation (within 72 h of ICU admission), mortality, and rate of adverse events. Data were extracted from free-text mobilisation entries using supervised machine learning (support vector machine). Statistical analyses were done using (generalised) linear (mixed-effect) models, as well as chi-square tests and ANOVAs. Results: A total of 12,462 patients were analysed in this study. They received a total of 59,415 mobilisation units. Of these patients, 842 (6.8%) received mobilisation under continuous norepinephrine administration. Norepinephrine administration was negatively associated with the frequency of mobilisation (adjusted difference -0.07 mobilisations per day; 95% CI - 0.09, - 0.05; p 0.1). Higher compared to lower doses of norepinephrine did not lead to a significant increase in adverse events in our practice (p > 0.1). We identified that mobilisation was safe with up to 0.20 mu g/kg/min norepinephrine for out-of-bed (IMS >= 2) and 0.33 mu g/kg/min for in-bed (IMS 0-1) mobilisation. Conclusions: Mobilisation with norepinephrine can be done safely when considering the status of the patient and safety guidelines. We demonstrated that safe mobilisation was possible with norepinephrine doses up to 0.20 mu g/kg/min for out-of-bed (IMS >= 2) and 0.33 mu g/kg/min for in-bed (IMS 0-1) mobilisation