Impact of insecticide treated mosquito nets and low dose monthly diethylcarbamazine on lymphatic filariasis infection between 1999 and 2004 in two endemic communities of north-eastern Tanzania

Lymphatic filariasis (LF) is among the poverty related neglected tropical diseases earmarked for elimination using mass drug administration (MDA) strategy. Additional use of insecticide treated mosquito nets (ITNs) might enhance elimination of LF infection. Between August 1998 and July 1999, all individuals aged ≥ 8 months from Magoda and Mpapayu villages in north-eastern Tanzania, were administered with monthly low dose diethylcarbamazine (DEC) at a dosage of 50mg in children aged < 15 years and 100mg in adults aged ≥ 15 years. ITNs were also distributed to Magoda in December 1998 and to Mpapayu in March 2001. The main objective of our study was to assess the impact of ITNs and low dose DEC on microfilaria (mf) prevalence and intensity and incidence of new mf infections. Four annual cross-sectional surveys were conducted between 1999 and 2004 in the two villages to screen for Wuchereria bancrofti microfilariae in individuals aged ≥ 1 year. Overall, 80% of the population in Magoda and 66% in Mpapayu were covered during these surveys. Results revealed a significant decrease in both mf prevalence and intensity in both villages. Furthermore, there was a steady decrease in mf incidence in Magoda; with 36.7 cases per 1000 person years in 2000 and 7.4 in 2004.  In Mpapayu, the incidence initially increased from 20.8 cases in 2000 to 24.3 in 2001 and then decreased to 7.2 cases in 2004.  Individuals using ITNs in Magoda had significantly lower risk of mf (OR=0.681; 95%CI: 0.496-0.934); and the risk of new infections was reduced by 58.8% (95%CI: 30.3-75.4). These results suggest that when MDA is complemented with ITNs there is high likelihood to half filariasis transmission within a shorter period than using chemotherapy alone

Acquisition of antibodies to merozoite surface protein 3 among residents of Korogwe, north eastern Tanzania

<p>Abstract</p> <p>Background</p> <p>A polymorphic malaria parasite antigen, merozoite surface protein 3 (MSP3), is among the blood stage malaria vaccine candidates. It is believed to induce immunity through cytophilic antibodies that disrupt the process of erythrocytes invasion by merozoites. This study aimed at assessing natural acquisition of antibodies to MSP3 in individuals living in an area with different malaria transmission intensity in preparation for malaria vaccine trials.</p> <p>Methods</p> <p>The study was conducted in individuals aged 0-19 years from villages located in lowland, intermediate and highland strata in Korogwe district, northeastern Tanzania. Blood samples from 492 study participants were collected between May and June 2006 for malaria diagnosis and immunological investigations. Reactivity of MSP3 to different types of antibodies (immunoglobulin M, G and IgG subclass 1 and 3) were analysed by Enzyme Linked ImmunoSorbent Assay (ELISA).</p> <p>Results</p> <p>Malaria parasite prevalence was higher in the lowland (50%) compared to the intermediate (23.1%) and highland (9.8%) strata. Immunogloblin G subclasses 1 and 3 (IgG1 & IgG3), total IgG and IgM were found to increase with increasing age. IgG3 levels were significantly higher than IgG1 (p < 0.001). Furthermore, <it>Plasmodium falciparum </it>infection was associated with higher IgG3 levels (p = 0.008). Adjusting by strata and age in individuals who had positive blood smears, both IgG and IgM were associated with parasite density, whereby IgG levels decreased by 0.227 (95%CI: 0.064 - 0.391; p = 0.007) while IgM levels decreased by 0.165 (95%CI: 0.044 - 0.286; p = 0.008).</p> <p>Conclusion</p> <p>Individuals with higher levels of IgG3 might be partially protected from malaria infection. Higher levels of total IgG and IgM in highlands might be due to low exposure to malaria infection, recent infection or presence of cross-reactive antigens. Further studies of longitudinal nature are recommended. Data obtained from this study were used in selection of one village (Kwashemshi) for conducting MSP3 phase 1b malaria vaccine trial in Korogwe.</p

Using Community-Owned Resource Persons to Provide Early Diagnosis and Treatment and Estimate Malaria Burden at Community Level in North-Eastern Tanzania.

Although early diagnosis and prompt treatment is an important strategy for control of malaria, using fever to initiate presumptive treatment with expensive artemisinin combination therapy is a major challenge; particularly in areas with declining burden of malaria. This study was conducted using community-owned resource persons (CORPs) to provide early diagnosis and treatment of malaria, and collect data for estimation of malaria burden in four villages of Korogwe district, north-eastern Tanzania.In 2006, individuals with history of fever within 24 hours or fever (axillary temperature ≥37.5°C) at presentation were presumptively treated using sulphadoxine/pyrimethamine. Between 2007 and 2010, individuals aged five years and above, with positive rapid diagnostic tests (RDTs) were treated with artemether/lumefantrine (AL) while under-fives were treated irrespective of RDT results. Reduction in anti-malarial consumption was determined by comparing the number of cases that would have been presumptively treated and those that were actually treated based on RDTs results. Trends of malaria incidence and slide positivity rates were compared between lowlands and highlands. Of 15,729 cases attended, slide positivity rate was 20.4% and declined by >72.0% from 2008, reaching <10.0% from 2009 onwards; and the slide positivity rates were similar in lowlands and highlands from 2009 onwards. Cases with fever at presentation declined slightly, but remained at >40.0% in under-fives and >20.0% among individuals aged five years and above. With use of RDTs, cases treated with AL decreased from <58.0% in 2007 to <11.0% in 2010 and the numbers of adult courses saved were 3,284 and 1,591 in lowlands and highlands respectively. Malaria incidence declined consistently from 2008 onwards; and the highest incidence of malaria shifted from children aged <10 years to individuals aged 10-19 years from 2009. With basic training, supervision and RDTs, CORPs successfully provided early diagnosis and treatment and reduced consumption of anti-malarials. Progressively declining malaria incidence and slide positivity rates suggest that all fever cases should be tested with RDTs before treatment. Data collected by CORPs was used to plan phase 1b MSP3 malaria vaccine trial and will be used for monitoring and evaluation of different health interventions. The current situation indicates that there is a remarkable changing pattern of malaria and these areas might be moving from control to pre-elimination levels

Rapid screening for glucose-6-phosphate dehydrogenase deficiency and haemoglobin polymorphisms in Africa by a simple high-throughput SSOP-ELISA method

BACKGROUND: Mutations in the haemoglobin beta-globin (HbB) and glucose-6-phosphate dehydrogenase (G6PD) genes cause widespread human genetic disorders such as sickle cell diseases and G6PD deficiency. In sub-Saharan Africa, a few predominant polymorphic variants of each gene account for a majority of these deficiencies. Examining at a larger scale the clinical importance of these independent genetic disorders, their possible association with malaria pathogenesis and innate resistance, and their relevance for antimalarial drug treatment, would be easier if an accurate screening method with limited costs was available. METHODS: A simple and rapid technique was developed to detect the most prominent single nucleotide polymorphisms (SNPs) in the HbB and G6PD genes. The method is able to detect the different haemoglobin polymorphisms A, S, C and E, as well as G6PD polymorphisms B, A and A- based on PCR-amplification followed by a hybridization step using sequence-specific oligonucleotide probes (SSOPs) specific for the SNP variants and quantified by ELISA. RESULTS: The SSOP-ELISA method was found to be specific, and compared well to the commonly used PCR-RFLP technique. Identical results were obtained in 98% (haemoglobin) and 95% (G6PD) of the tested 90 field samples from a high-transmission area in Tanzania, which were used to validate the new technique. CONCLUSION: The simplicity and accuracy of the new methodology makes it suitable for application in settings where resources are limited. It would serve as a valuable tool for research purposes by monitoring genotype frequencies in relation to disease epidemiology

Saleability of Anti-malarials in Private Drug Shops in Muheza, Tanzania: A Baseline study in an era of assumed Artemisinin Ccombination Therapy (ACT).

Artemether-lumefantrine (ALu) replaced sulphadoxine-pymimethamine (SP) as the official first-line anti-malarial in Tanzania in November 2006. So far, artemisinin combination therapy (ACT) is contra-indicated during pregnancy by the national malaria treatment guidelines, and pregnant women depend on SP for Intermittent Preventive Treatment (IPTp) during pregnancy. SP is still being dispensed by private drug stores, but it is unknown to which extent. If significant, it may undermine its official use for IPTp through induction of resistance. The main study objective was to perform a baseline study of the private market for anti-malarials in Muheza town, an area with widespread anti-malarial drug resistance, prior to the implementation of a provider training and accreditation programme that will allow accredited drug shops to sell subsidized ALu. All drug shops selling prescription-only anti-malarials, in Muheza town, Tanga Region voluntarily participated from July to December 2009. Qualitative in-depth interviews were conducted with owners or shopkeepers on saleability of anti-malarials, and structured questionnaires provided quantitative data on drugs sales volume. All surveyed drug shops illicitly sold SP and quinine (QN), and legally amodiaquine (AQ). Calculated monthly sale was 4,041 doses, in a town with a population of 15,000 people. Local brands of SP accounted for 74% of sales volume, compared to AQ (13%), QN (11%) and ACT (2%). In community practice, the saleability of ACT was negligible. SP was best-selling, and use was not reserved for IPTp, as stipulated in the national anti-malarial policy. It is a major reason for concern that such drug-pressure in the community equals de facto intermittent presumptive treatment. In an area where SP drug resistance remains high, unregulated SP dispensing to people other than pregnant women runs the risk of eventually jeopardizing the effectiveness of the IPTp strategy. Further studies are recommended to find out barriers for ACT utilization and preference for self-medication and to train private drug dispensers

Addressing the fear and consequences of stigmatization - a necessary step towards making HAART accessible to women in Tanzania: a qualitative study

<p>Abstract</p> <p>Background</p> <p>Highly Active Antiretroviral Therapy (HAART) has been available free of charge in Tanga, Tanzania since 2005. However we have found that a high percentage of women referred from prevention of mother-to-child transmission services to the Care and Treatment Clinics (CTC) for HAART never registered at the CTCs. Few studies have focused on the motivating and deterring factors to presenting for HAART particularly in relation to women. This study seeks to remedy this gap in knowledge.</p> <p>Methodology</p> <p>A qualitative approach using in-depth interviews and focus group discussions was chosen to understand these issues as perceived and interpreted by HIV infected women themselves.</p> <p>Results</p> <p>The main deterrent to presenting for treatment appears to be fear of stigmatization including fear of ostracism from the community, divorce and financial distress. Participants indicated that individual counselling and interaction with other people living with HIV encourages women, who are disinclined to present for HAART, to do so, and that placing the entrance to the CTC so as to provide discrete access increases the accessibility of the clinic.</p> <p>Conclusion</p> <p>Combating stigma in the community, although it is essential, will take time. Therefore necessary steps towards encouraging HIV infected women to seek treatment include reducing self-stigma, assisting them to form empowering relationships and to gain financial independence and emphasis by example of the beneficial effect of treatment for themselves and for their children. Furthermore ensuring a discrete location of the CTC can increase its perceived accessibility.</p

Eliciting harms data from trial participants: how perceptions of illness and treatment mediate recognition of relevant information to report

Background: There is no consensus on the ideal methodology for eliciting participant-reported harms, but question methods influence the extent and nature of data detected. This gives potential for measurement error and undermines meta-analyses of adverse effects. We undertook to identify barriers to accurate and complete reporting of harms data, by qualitatively exploring participants’ experiences of illness and treatment, and reporting behaviours; and compared the number and nature of data detected by three enquiry methods. Methods: Participants within antiretroviral/antimalarial interaction trials in South Africa and Tanzania were asked about medical history, treatments and/or adverse events by general enquiries followed by checklists. Those reporting differently between these two question methods were invited to an in-depth interview and focus group discussion. Health narratives were analysed to investigate accuracy and completeness of case record form data and to understand reasons for differential reporting between question methods. Outcomes were the number and nature of data by question method, themes from qualitative analyses and a theoretical interpretation of participants’ experiences. Results: We observed a cumulative increase in sensitivity of detection of all types of reports while progressing from general enquiry, through checklist, to in-depth interview. Questioning detail and terminology influenced participants’ recognition of health issues and treatments. Reporting patterns and vocabulary suggest influence from the relative importance that illnesses and treatments have for participants. Perceptions were often dichotomised (e.g. ‘street’ versus clinic treatments, symptoms experienced versus tests and examinations performed, chronic versus acute illness, persistent versus intermittent symptoms, activity- versus malaria-related symptoms) and this differentiation extended to ideas of relevance to report. South African participants displayed a ‘trial citizenship’, taking responsibility for the impact of their reporting on trial results, and even reaching reporting decisions by consensus. In contrast, Tanzanians perceived their role more as patients than participants; the locus of responsibility for knowing information relevant to the trial fell with trial staff as doctors rather than with themselves. Conclusions: Our observations of how reporting relates to participant perceptions inside and outside trials could help optimise how harms data are elicited. Questions reflecting the different ways that biomedically defined illness and treatment data are perceived by participants may help them understand relevance for reporting. We will theorise how these two disparate trial environments may have influenced how participants understood their role, as this could help researchers achieve empowered participation in similar trials

Acceptability of malaria rapid diagnostic tests administered by village health workers in Pangani District, North eastern Tanzania.

BACKGROUND: Malaria continues to top the list of the ten most threatening diseases to child survival in Tanzania. The country has a functional policy for appropriate case management of malaria with rapid diagnostic tests (RDTs) from hospital level all the way to dispensaries, which are the first points of healthcare services in the national referral system. However, access to these health services in Tanzania is limited, especially in rural areas. Formalization of trained village health workers (VHWs) can strengthen and extend the scope of public health services, including diagnosis and management of uncomplicated malaria in resource-constrained settings. Despite long experience with VHWs in various health interventions, Tanzania has not yet formalized its involvement in malaria case management. This study presents evidence on acceptability of RDTs used by VHWs in rural northeastern Tanzania. METHODS: A cross-sectional study using quantitative and qualitative approaches was conducted between March and May 2012 in Pangani district, northeastern Tanzania, on community perceptions, practices and acceptance of RDTs used by VHWs. RESULTS: Among 346 caregivers of children under 5 years old, no evidence was found of differences in awareness of HIV rapid diagnostic tests and RDTs (54 vs. 46 %, p = 0.134). Of all respondents, 92 % expressed trust in RDT results, 96 % reported readiness to accept RDTs by VHWs, while 92 % expressed willingness to contribute towards the cost of RDTs used by VHWs. Qualitative results matched positive perceptions, attitudes and acceptance of mothers towards the use of RDTs by VHWs reported in the household surveys. Appropriate training, reliable supplies, affordability and close supervision emerged as important recommendations for implementation of RDTs by VHWs. CONCLUSION: RDTs implemented by VHWs are acceptable to rural communities in northeastern Tanzania. While families are willing to contribute towards costs of sustaining these services, policy decisions for scaling-up will need to consider the available and innovative lessons for successful universally accessible and acceptable services in keeping with national health policy and sustainable development goals

Malaria morbidity and immunity among residents of villages with different Plasmodium falciparum transmission intensity in North-Eastern Tanzania

BACKGROUND: The relationship between the burden of uncomplicated malaria and transmission intensity is unclear and a better understanding of this relationship is important for the implementation of intervention programmes. METHODS: A 6-month longitudinal study monitoring risk factors for anaemia and febrile malaria episodes was conducted among individuals aged below 20 years, residing in three villages of different altitude in areas of high, moderate and low malaria transmission intensity in North-Eastern Tanzania. RESULTS: The burden of anaemia and malarial fever fell mainly on the youngest children and was highest in the village with high transmission intensity. Although a considerable percentage of individuals in all villages carried intestinal worms, logistic regression models indicated that Plasmodium falciparum was the only significant parasitic determinant of anaemia. Interestingly, children who carried low-density parasitaemia at the start of the study had a lower risk of contracting a febrile malaria episode but a higher risk of anaemia during the study period, than children who were slide negative at this point in time. CONCLUSION: Young children living in the high transmission village carried a very high anaemia burden, which could be attributed to malaria. The overall incidence of febrile malaria was also highest in the high transmission village particularly among those under five years of age. These data suggest that in rolling back malaria, available resources in prevention programmes should primarily be focussed on young children, particularly those residing in areas of high malaria transmission

Declining Burden of Malaria Over two Decades in a Rural Community of Muheza District, North-Eastern Tanzania.

The recently reported declining burden of malaria in some African countries has been attributed to scaling-up of different interventions although in some areas, these changes started before implementation of major interventions. This study assessed the long-term trends of malaria burden for 20 years (1992--2012) in Magoda and for 15 years in Mpapayu village of Muheza district, north-eastern Tanzania, in relation to different interventions as well as changing national malaria control policies.\ud Repeated cross-sectional surveys recruited individuals aged 0 -- 19 years from the two villages whereby blood smears were collected for detection of malaria parasites by microscopy. Prevalence of Plasmodium falciparum infections and other indices of malaria burden (prevalence of anaemia, splenomegaly and gametocytes) were compared across the years and between the study villages. Major interventions deployed including mobile clinic, bed nets and other research activities, and changes in national malaria control policies were also marked. In Magoda, the prevalence of P. falciparum infections initially decreased between 1992 and 1996 (from 83.5 to 62.0%), stabilized between 1996 and 1997, and further declined to 34.4% in 2004. A temporary increase between 2004 and 2008 was followed by a progressive decline to 7.2% in 2012, which is more than 10-fold decrease since 1992. In Mpapayu (from 1998), the highest prevalence was 81.5% in 1999 and it decreased to 25% in 2004. After a slight increase in 2008, a steady decline followed, reaching <5% from 2011 onwards. Bed net usage was high in both villages from 1999 to 2004 (>=88%) but it decreased between 2008 and 2012 (range, 28% - 68%). After adjusting for the effects of bed nets, age, fever and year of study, the risk of P. falciparum infections decreased significantly by >=97% in both villages between 1999 and 2012 (p < 0.001). The prevalence of splenomegaly (>40% to <1%) and gametocytes (23% to <1%) also decreased in both villages.Discussion and conclusionsA remarkable decline in the burden of malaria occurred between 1992 and 2012 and the initial decline (1992 -- 2004) was most likely due to deployment of interventions, such as bed nets, and better services through research activities. Apart from changes of drug policies, the steady decline observed from 2008 occurred when bed net coverage was low suggesting that other factors contributed to the most recent pattern. These results suggest that continued monitoring is required to determine causes of the changing malaria epidemiology and also to monitor the progress towards maintaining low malaria transmission and reaching related millennium development goals