Plasmodium species in Zambia

Sitali L, Miller JM, Mwenda MC, Bridges DJ, Hawela MB, Hamainza B, Chizema-Kawesha E, Eisele TP, Chipeta J, Lindtjørn B: Distribution of Plasmodium species and assessment of performance of diagnostic tools used during a malaria survey in Southern and Western Provinces of Zambia. Malaria Journal 2019, 18:130.

Background  Zambia continues to make strides in reducing malaria burden through the use of proven malaria interventions and has recently pledged to eliminate malaria by 2021. Case management services have been scaled up at community level with rapid diagnostic tests (RDTs) providing antigen-based detection of falciparum malaria only. Key to national malaria elimination goals is the ability to identify, treat and eliminate all Plasmodium species. This study sought to determine the distribution of non-falciparum malaria and assess the performance of diagnostic tests for Plasmodium falciparum in Western and Southern Provinces of Zambia, two provinces planned for early malaria elimination.

Methods  A sub-set of individuals’ data and samples from a cross-sectional household survey, conducted during peak malaria transmission season in April and May 2017, was used. The survey collected socio-demographic information on household members and coverage of malaria interventions. Malaria testing was done on respondents of all ages using blood smears and RDTs while dried blood spots were collected on filter papers for analysis using photo-induced electron transfer polymerase chain reaction (PET-PCR). Slides were stained using Giemsa stain and examined by microscopy for malaria parasites.

Results  From the 1567 individuals included, the overall prevalence of malaria was 19.4% (CI 17.5–21.4) by PCR, 19.3% (CI 17.4–21.4) by RDT and 12.9% (CI 11.3–14.7) by microscopy. Using PET-PCR as the gold standard, RDTs showed a sensitivity of 75.7% (CI 70.4–80.4) and specificity of 94.2% (CI 92.8–95.4). The positive predictive value (PPV) was 75.9% (CI 70.7–80.6) and negative predictive value (NPV) was 94.1% (CI 92.1–95.4). In contrast, microscopy for sensitivity, specificity, PPV, and NPV values were 56.9% (CI 51.1–62.5), 97.7% (CI 96.7–98.5), 85.6% (CI 80.0–90.2), 90.4% (CI 88.7–91.9), respectively. Non-falciparum infections were found only in Western Province, where 11.6% of P. falciparum infections were co-infections with Plasmodium ovale or Plasmodium malariae.

Conclusion  From the sub-set of survey data analysed, non-falciparum species are present and occurred as mixed infections. As expected, PET-PCR was slightly more sensitive than both malaria RDTs and microscopy to detecting malaria infections.

New PhD by Alemayehu Hailu: Economic evaluation of malaria prevention in Ethiopia

Thesis_UiB_Alemayehu_Hailu

Hailu A, D. Economic evaluation of malaria prevention in Ethiopia: Economic burden, equity, and cost-effectiveness analysis of malaria prevention in south-central Ethiopia [PhD]. Bergen: University of Bergen; 2018.

Summary
Background: Despite remarkable efforts in the global fight against malaria and achievements in the reduction of morbidity and mortality in the last decade, the disease remains to be a huge challenge to the health systems of malaria-endemic low-income countries in Africa and in all corners of the globe. Beyond the wide range of consensus on the disease burden and prioritization of malaria, the available evidence on the economic burden of malaria in Ethiopia is scanty. No clear evidence yet exists about the additional resources required for a combined implementation of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) with respect to the added protection afforded. In addition, little is known about the prevailing status of LLINs and IRS across different levels of wealth strata.

Objectives: The aims of this thesis were to estimate the economic burden of malaria; to evaluate the cost-effectiveness of a combined implementation malaria prevention interventions (LLINs and IRS); and analyse the distributional (equity) implications of the interventions in the Adami Tullu district, south-central Ethiopia.

Methods: Studies included in this thesis were conducted from 2014 – 2016 in the Adami Tullu district of Oromia Region, in south-central Ethiopia as part of and partly in conjunction with the MalTrials project. We conducted a cost of illness using 190 malaria patients in the first study. In Paper II, we carried out a combination of trial-based and literature-based cost-effectiveness analysis using Markov modelling. In the third study, using a cross-sectional data from 6069 households we did an inequality analysis of ownership of LLINs and IRS status. The principal component analysis technique was used for ranking households based on socioeconomic position. We measured the inequality in LLINs and IRS using concentration indices and concentration curve (Paper I&III).

Results: The median cost of malaria per episode to the household was USD 5.06 (IQR: 2.98 – 8.10) and the direct cost was significantly higher among the poor. The trial-based analysis had shown that the routine practice dominates both the combined intervention and singleton intervention while the literature-based analysis had indicated that combined intervention had an Incremental Cost-Effectiveness Ratio of USD 1403 per DALY averted. Immediately before we started the trial, the LLIN ownership was 11.6% and IRS coverage was 72.5%. We found a concentration index of 0.0627 for LLINs and – 0.0383 for the IRS. Inequality in LLIN ownership was mainly associated with a variability in a housing situation, the size of the household, and access to mass media and telecommunication service.

Conclusions: The economic burden of malaria to the rural households in Ethiopia is huge—mainly to the poor. Based on the trial-based cost-effectiveness analysis, we conclude that the combination of LLINs and IRS is not likely to be a cost-effective option compared with singleton intervention. However, based on the literature-based analysis, the combined intervention had potential to be a cost-effective alternative at 3 times GDP per capita per DALY averted. Furthermore, the ownership of LLIN was very low and significantly pro-rich, while IRS status was equitable across socioeconomic strata.

New and important publication from the Arba Minch group

Mulchandani R, Massebo F, Bocho F, Jeffries CL, Walker T, Messenger LA. A community-level investigation following a yellow fever virus outbreak in South Omo Zone, South-West Ethiopia. PeerJ. 2019;7. doi: 10.7717/peerj.6466.

Background

Despite the availability of a highly effective vaccine, yellow fever virus (YFV) remains an important public health problem across Africa and South America due to its high case-fatality rate. This study investigated the historical epidemiology and contemporary entomological and social determinants of a YFV outbreak in South Omo Zone (SOZ), Ethiopia.

Methods

A YFV outbreak occurred in SOZ, Ethiopia in 2012–2014. Historical epidemiological data were retrieved from the SOZ Health Department and analyzed. Entomological sampling was undertaken in 2017, including mosquito species identification and molecular screening for arboviruses to understand mosquito habitat distribution, and finally current knowledge, attitudes and preventative practices within the affected communities were assessed.

Results

From October 2012 to March 2014, 165 suspected cases and 62 deaths were reported, principally in rural areas of South Ari region (83.6%). The majority of patients were 15–44 years old (75.8%) and most case deaths were males (76%). Between June and August 2017, 688 containers were sampled across 180 households to identify key breeding sites for Aedesmosquitoes. Ensete ventricosum (“false banana”) and clay pots outside the home were the most productive natural and artificial breeding sites, respectively. Entomological risk indices classified most sites as “high risk” for future outbreaks under current World Health Organization criteria. Adult mosquitoes in houses were identified as members of the Aedes simpsonicomplex but no YFV or other arboviruses were detected by PCR. The majority of community members had heard of YFV, however few activities were undertaken to actively reduce mosquito breeding sites.

Discussion

Study results highlight the potential role vector control could play in mitigating local disease transmission and emphasize the urgent need to strengthen disease surveillance systems and in-country laboratory capacity to facilitate more rapid responses to future YFV outbreaks.

 

Taye Gari’s PhD thesis: Malaria, anaemia and undernutrition in Ethiopia

Taye Gari. Malaria, anaemia and undernutrition in a drought-affected area of the Rift Valley of Ethiopia: Experiences from a trial to prevent malaria.  PhD. University of Bergen, 2018. Bergen

Summary of PhD thesis

Background: In Ethiopia, malaria, anaemia and undernutrition are common childhood health problems. The country is planning to reduce these conditions to a level where they are not a public health problem. Meanwhile, for the success of this aim, a description of the occurrence and interaction of malaria, anaemia and undernutrition could help contribute to design tailored, efficient and effective control strategies. This study was done in the context of malaria prevention trial, which aimed to measure the effect of combining long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) in reducing the malaria incidence compared to LLINs or IRS alone. The study area was affected by a serious drought and famine during the first year of the study.

Objectives: The overall aim of this thesis is to improve our understanding of the effect of malaria prevention on anaemia, and to assess the association between malaria, anaemia and undernutrition among children in a drought-affected area in south-central, Ethiopia.

Methods: A cohort of 5309 residents was followed-up for 16 weeks to measure the variations in malaria incidence among villages (Paper I), and the results were used as a baseline to calculate the sample size needed for the trial. We followed a cohort of children aged 6 to 59 months for one year to describe anaemia and changes in haemoglobin (Hb) concentration (Paper II). A cohort of 4468 children was followed-up for 89 weeks to measure the relationship between malaria and undernutrition (Paper III). Weekly home visits and patient self-referral were also used to identify malaria cases. We conducted Hb concentration (once a year) and anthropometry (twice a year) surveys.

Results: In Paper I, we observed a variation in malaria incidence among villages. On the other hand, the insecticide-treated nets ownership was low (27%), with the distance from the lake or river and younger age being the main risk factors for malaria. The findings of this study were used as a baseline to calculate the sample size for the trial. In Paper II, despite the malaria prevention effort in the community, we observed an unexpected increase in anaemia prevalence over the period of a year, which could be due to the drought and famine that affected the area. A higher incidence of anaemia was observed among children with stunting, malaria infection, young age and in poor families. However, no significant difference in anaemia prevalence was observed among the different trial arms (LLIN+IRS, LLINs alone, IRS alone and routine arm). In Paper III, malaria infection was a risk factor for stunting and wasting, although undernutrition was not a risk for malaria infection. Furthermore, an increase in the prevalence of stunting, but no significant change in a prevalence of wasting was observed over time.

Conclusions: We showed a large variation in malaria incidence among villages. Conducting trials in a drought-prone area may bring an unexpected challenge. We observed an unexpected increase in anaemia prevalence over a year. There was no significant difference in anaemia prevalence among the trial arms. Moreover, a close follow-up of the nutritional status of children with malaria infection may be needed. There could hence be a need to prioritize villages nearer to the main mosquito breeding sites for malaria control.

Trial registration: PACTR 201411000882128 (8 September, 2014)

The Thesis can be downloaded here

Malaria, anaemia and undernutrition

On Friday June 22, 2018 Taye Gari Anaya will defend his PhD thesis at the University of Bergen. 

The title of his thesis is: “Malaria, anaemia and undernutrition in a drought-affected area of the Rift Valley of Ethiopia: Experiences from a trial to prevent malaria”.

Malaria, anaemia and malnutrition are interconnected, and often coexist in prevalent areas such as in sub-Saharan Africa, including Ethiopia. Although individuals in all ages of life are affected by these conditions, children under the age of 5 represent the most vulnerable group. Ethiopia is planning to reduce these conditions to a level where they are not public health problems Meanwhile, for the success of this aim, a description of the occurrence and interaction of malaria, anaemia and undernutrition could help to design tailored, efficient and effective control strategies.  

This thesis measures the effect of malaria prevention on anaemia reduction, and assesses the association between malaria, anaemia and undernutrition among a cohort of children aged 6 to 59 months old followed in a drought-affected rural area in south-central, Ethiopia.

The study showed a large variation in malaria incidence among villages in the same district. Despite community wide malaria prevention effort, an unexpected increase in anaemia prevalence was observed over a year. Malaria infection was a risk factor for undernutrition, although undernutrition was not a risk for malaria infection. There could be a need to prioritise villages nearer to the main mosquito breeding sites for malaria control. Moreover, a close follow-up of the nutritional status of children with malaria infection may be needed. 

Biographical

Taye Gari Ayana is from Hawassa in south Ethiopia. He completed Master degree in Public Health from Addis Ababa University in Ethiopia. From 2013 he has been affiliated with the Centre for International Health as a PhD candidate. Now he is a lecturer at the School of Public Health, at Hawassa University in Ethiopia. His supervisors were Professor Bernt Lindtjørn, Dr Eskindir Loha and Dr Wakgari Deressa. 

Maternal Mortality and Stillbirths More than Halved

The 2017 Annual report from the Centre for International Health at the University of Bergen writes about the implementation reserach in south Ethiopia:

Making standard delivery services available for all is the most important factor for improving maternal mortality. Furthermore, the study suggests that stillbirths can also be reduced if the health services focus on improved obstetric care.

Professor Bernt Lindtjørn led a project in south-western Ethiopia studying how a number of interventions could reduce maternal mortality and stillbirths. As a result of the research efforts, there was 64% reduction in maternal mortality and a 46% reduction in stillbirths.

Lindtjørn explains that there are several reasons why mothers die in childbirth, but he highlights that the main causes are insufficient numbers of institutions and trained personnel, as well as a lack of access to services (i.e. transportation) as being the most important factors.

The project’s positive results were associated with increasing the numbers of trained staff, increasing the num- bers of institutions undertaking Comprehensive Emergency Obstetric Care (CEmOC), increasing the numbers of mothers having Caesarean sections, increasing in the numbers of antenatal controls and referrals, improving access to health service, decreasing in number of home deliveries and decreasing the use of traditional birth attendants.

The goals for the project were straight forward and included making small hospitals available for rural popu- lations, improving referrals (i.e. from health posts to health centres to hospitals when necessary), undertaking additional training for non-clinical physicians, nurses, midwives, and health extension workers, making essential equipment available, and supervising the health care services on offer.

The project was based on the principle of “learning by doing” and involved short courses in Basic Emergen- cy Obstetric Care (BEmOC) and Comprehensive Emergency Obstetric Care (CEmOC), as well as anaesthesiolo- gy, scrub nursing and Continuing Medical Education (CME). It also included Master and PhD training in Public Health: one PhD and 6 master degrees resulted from the project.

The publications from this project can be viewed here.

The risk for death remains high for patients treated for tuberculosis in Ethiopia

Dangisso MH, Woldesemayat EM, Datiko DG, Lindtjorn B. Long-term outcome of smear-positive tuberculosis patients after initiation and completion of treatment: A ten-year retrospective cohort study. PLoS One. 2018;13(3):e0193396. Epub 2018/03/13. doi: 10.1371/journal.pone.0193396. PubMed PMID: 29529036; PubMed Central PMCID: PMCPMC5846790.

Background: The status of tuberculosis (TB) patients since initiation of treatment is unknown in South Ethiopia. The objective of this study was to assess the long-term outcomes of smear-positive TB patients since initiation and completion of treatment, which includes TB recurrence and mortality of TB patients.

Methods: We did a retrospective cohort study on 2,272 smear-positive TB patients who initiated treatment for TB from September 1, 2002-October 10, 2012 in health facilities in Dale district and Yirgalem town administration. We followed them from the date of start of treatment to either the date of interview or date of death.

Results: Recurrence rate of TB was 15.2 per 1000 person-years. Recurrence was higher for re-treatment cases (adjusted hazard ratio (aHR), 2.7; 95% CI, 1.4-5.3). Mortality rate of TB patients was 27.1 per 1,000 person-years. The risk was high for patients above 34 years of age (aHR, 2.1; 95% CI, 1.2-3.9), poor patients (aHR, 1.3; 95% CI, 1.0-1.8), patients with poor treatment outcomes (aHR, 6.7; 95% CI, 5.1-8.9) and for patients treated at least 3 times (aHR 4.8; 95% CI, 2.1-11.1). The excess mortality occurred among patients aged above 34 years was high (41.2/1000 person years).

Conclusions: High TB recurrence and death of TB patients was observed among our study participants. Follow-up of TB patients with the risk factors and managing them could reduce the TB burden.

Successful midway evaluations for 7 PhD students at Hawassa University

On Thursday April 25, seven PhD students admitted to the joint PhD degree programme between the Hawassa University and the University of Bergen, had their mid-way evaluations. Evaluators were senior staff from both Hawassa University and the University of Bergen.

The midway evaluation has the following goals:

  • to find the status regarding the progress and development of the individual PhD project
  • to give the candidate the possibility to present the whole project for a committee

The following students presented their research:

Alemselam Zebdewos: Preventing iron deficiency anaemia: Evaluation of amaranth grain supplementation to 2-5 years old children in southern Ethiopia, a randomized controlled trial

Samrawit Hailu: Childhood illness and health service utilization in Wonago District, South Ethiopia. A community –based cohort study

Sewhareg Belay: Intimate Partner violence during pregnancy: Prevalence, health effect and knowledge about it in Sidama zone, Southern Ethiopia

Hiwot Hailu: Assessment of school health problems in Gedeo Zone, Southern Ethiopia

Bereket Yohannes: Assessing validity of the ‘Household Food Insecurity Access Scale’, and seasonality in food insecurity and undernutrition in rural Southwest Ethiopia

Mehretu Belayneh: Magnitude, seasonality and spatial distribution of under-nutrition among children aged 6-59 months, Boricha, Southern Ethiopia

Moges Tadesse: Maternal and Neonatal illnesses, its economic burden, and health service utilisation in rural Ethiopia: A community-based prospective cohort study

Residual malaria transmission

Abraham M, Massebo F, Lindtjørn B: High entomological inoculation rate of malaria vectors in area of high coverage of interventions in southwest Ethiopia: Implication for residual malaria transmission. Parasite Epidemiology and Control 2017, 2:61-69.

Abstract
In Ethiopia, vector control is the principal strategy to reduce the burden of malaria. The entomological indicators of malaria transmission such as density, sporozoite rate and entomological inoculation rate (EIR) are parameters used to assess the impact of the interventions and the intensity of malaria transmission. The susceptibility of malaria vectors also determines the effectiveness of insecticide based vector control tools. Hence, the aim of the study was to assess the species composition, sporozoite rate and EIR, and insecticide susceptibility status of malaria vectors.

33 houses (18 for Centre for Disease Control and Prevention (CDC) light traps and 15 for exit traps) were randomly selected to sample Anopheles mosquitoes from October 2015 to May 2016. Plasmodium circum-sporozoite proteins (CSPs) of An. arabiensis and An. pharoensis were determined using Enzyme-Linked Immuno-Sorbent Assay (ELISA).

Five Anopheles species were identified from CDC Light traps and exit traps. An. arabiensis (80.2%) was the predominant species, followed by An. pharoensis (18.5%). An. pretoriensis, An. tenebrosus and An. rhodesiensis were documented in small numbers. 1056 Anopheles mosquitoes were tested for CSPs. Of which nine (eight An. arabiensis and one An. pharoensis) were positive for CSPs with an overall CSP rate of 0.85% (95% CI: 0.3–1.4). Five Anopheles mosquitoes were positive for P. falciparumand four were positive for P.vivax_210. P. falciparum CSP rate of An. arabiensis was 0.46% (95% CI: 0.13–1.2) and it was 0.54% (95% CI: 0.01–2.9) for An. pharoensis. The overall EIR of An. arabiensis was 5.3 infectious bites per/person (ib/p)/eight months. An. arabiensis was resistant to dieldrin (mortality rate of 57%) and deltamethrin with mortality rates of 71% but was fully susceptible to propoxur and bendiocarb. Based on the EIR of An. arabiensis, indoor malaria transmission was high regardless of high coverage of indoor-based interventions.

Finally, there was an indoor residual malaria transmission in a village of high coverage of bed nets and where the principal malaria vector is susceptibility to propoxur and bendiocarb; insecticides currently in use for indoor residual spraying. The continuing indoor transmission of malaria in such village implies the need for new tools to supplement the existing interventions and to reduce indoor malaria transmission.

The epidemiology of highland malaria in Ethiopia: a study from Butajira area

On May 30th, 2013, Adugna Woyessa defended his PhD thesis at Addis Ababa University. The PhD thesis The epidemiology of highland malaria in Ethiopia: a study from Butajira area aims to  describe human malaria transmission  in rural south central Ethiopian highlands.

Abstract

Background:In Ethiopia, malaria is a major public health problem with seasonal and unstable distribution. Because of the country’s diverse topography and climate, transmission of malaria varies with space and time; while the variability is more pronounced in highlands with low transmission. This calls for better understanding of malaria. However, there is paucity of information on magnitudeof malaria, risk factors, effective use of vector control measures such as insecticide-treated nets in relationship with malaria infection and performance of multi-species detecting malaria rapid diagnostic tests (RDTs) where Plasmodium falciparum and Plasmodium vivax co-exist at highlands of low-endemicity.

Objectives:To describe the epidemiology of highland malaria with emphasis to the magnitude and associated factors as well as interventions in various altitudesof Butajira area, south-central Ethiopia.

METHODS: Community-based repeated cross-sectional studies were conducted in six rural kebeles of Meskan and Mareko Districts from October 2008 to June 2010in Butajira area, Ethiopia. The kebeles (Hobe, Bati Lejano, Dirama, Shershera Bido, Yeteker and Wurib) were selected in such a way that two were from one altitudinal stratum thus making a total of three strata: low (1,800-1,899 meters above sea level), mid-level (1,900-1,999 meters above sea level), and high (2,000-2,300 meters above sea level) altitudes. These kebeles are part of Demographic Surveillance System Site of the Butajira Rural Health Program). A multi-stage sampling method was used to recruit study participants. The various stages were kebeles as first-stage, villages as second-stage, and households as third-stage units.   A total of 3,393 individuals were recruited from randomly sampled 750 households in 16 villages. Probability proportion to size sampling method was applied to allocate the number of households to be sampled from each kebeleand village. The study obtained data from household interview, survey and recruiting all self-reported febrile cases.  Household interview was undertaken by trained data collectors using pre-tested structured questionnaire. Household altitude reading and geo-reference was recorded from geographical positioning system location. Seasonal blood surveys were made on quarterly basis between Oct. 2008 and Jun. 2010. From the sampled households, all family members who consented to participate were requested for blood films. Besides, self-reported febrile cases were simultaneously checked for malaria infection using RDTs. CareStartTMMalaria Plasmodium falciparum/ Plasmodium vivax combo test result was compared with microscopy. Analytical tools including descriptive statistics, multilevel analysis, principal component analysis, and complex sample analysis were employed.

Main findings: The unadjusted prevalence of malaria was found to be 0.93 % [95% CI 0.79-1.07]; of 19, 207 people, 178 were positive; adjusted prevalence of malaria was estimated at 0.78 (95% CI: 0.48-1.29); of 19, 199 people, 178 were positive. Plasmodium vivax was dominant (86.5%, n=154) and the rest of the cases were due to Plasmodium falciparum (12.4%, n=22, seven with gametocyte) and mixed infections (1.1%, n=2).The prevalence varied among villages with the highest prevalence of 2.8% in Dadesso and Horosso villages (both <1,850 masl), and the lowest prevalence of 0.0% in Sunke Wenz and Akababi village (2,100-2,180 masl). Malaria prevalence decreased with altitude: 1.91% [95% CI (1.55-2.27)] in low, 1.37% [95% CI (0.87-1.87)] in mid-level and 0.36% [95% CI (0.25-0.47)] in high altitude zones; the highest prevalence was found at low altitude between October and November 2009. Moreover, malaria varied among age groups and the variation was different at different at altitudes. It reached its peak in children aged one to four yearsYonkers at mid-level and one to nine years at low altitudes. However, its prevalence at higher altitude was low and was similar across all age groups. Plasmodium falciparum malaria occurred rarely throughout the survey periods, with relatively more cases in October-November 2009 in the low altitude zone. Plasmodium vivax was found in all survey periods. However, its prevalence differed with respect to survey period and altitude. Variables like age (children aged below five and 5-9 years), altitude (low and mid-level altitude), and in houses with holes as individual-level factors; and village-level variables explained most of the variation (ICC= 94%) in individual malaria infection. The estimates of village-level variances showed well marked differences in malaria infection.

Only 28.5% [95%CI 25.8-31.4] of the 739 households surveyed owned at least an ITN.  Household ITN ownership was associated with household heads with no formal education, male-headed households, more beds in the house, absence of mosquito source reduction, and nonexistence of main water body. Male-headed households were also more associated with increased ITN ownership than female-headed ones. Households with ITN observed hanging, two and more number of ITN owned, not doing source reduction and less than a kilometredistance from main water body showed high association with use of ITN while the presence of more ITN observed hanging was a good predictor. Higher prevalence was found among people surveyed from ITN-owning than non-ITN-owning households (2.1% versus 0.5%). Malaria infection was more often observed in households owning at least an ITN than in their counterparts (unadjusted OR 4.1 [95% C.I. 2.2-7.6]; F (1, 22) =25.2, P<0.001).

Data obtained from a total of 2,394 self-reported febrile cases: 66.8% (n=1,598) from health facilities and the rest 33.2% (n=796) from surveys. Higher proportionof Plasmodium positives and both Plasmodium falciparum and Plasmodium vivaxwere detected at health facilities compared to what was seen in the survey. However, more mixed infections were observed in the latter. Low sensitivity of the test was observed in all Plasmodium species (90.8%, 95% CI: 82.9-95.3), and Plasmodium falciparum (87.5%, 52.9-97.8) in survey; and Plasmodium vivax (92.8%, 95% CI: 89.3-95.2) at health facilities. Low specificity of Plasmodium vivax (87.5%, 95% CI: 52.9-97.8) was found at the survey and all Plasmodium species (82.7%, 95% CI: 80.5-84.8) at health facilities. Very low PPV was detected in all Plasmodium species (76.7%, 95% CI: 67.7-83.8), and Plasmodium falciparum (87.5%, 95% CI: 52.9-97.8) at the survey and all Plasmodium species (64.3%, 95% CI: 60.5-68.1) and Plasmodium falciparum (77.2%, 95% CI: 67.6-84.5) at health facilities.  Low NPV was observed in Plasmodium vivax both in the survey (87.5%, 95% CI: 52.9-97.8) and health facilities (77.2: 67.6-84.5).The measure of agreement or kappa score was almost perfect agreement in all categories, except in all Plasmodium species with substantial agreement.

Conclusions and recommendations: This thesis demonstrates that low prevalence of malaria with age and altitude dependent distribution was found in highlands with low transmission in south-central Ethiopia. Plasmodium vivax was the dominant species more prevalent throughout the survey. There was very low ITN use that might have also hardly protected children in ITN-owning households. Performance of malaria RDT detecting Plasmodium falciparum and Plasmodium vivax vary between health facility-based and survey setting for both species. A malaria intervention that prioritises children below 10 years appears to be practically feasible to reduce malaria transmission. Strengthening surveillance to help in evidence-informed decision of vector control is recommendable. Furthermore, future studies should target designing more frequent survey and application of PCR for evaluation of RDT performance.

Publications:

Woyessa A, Deressa W, Ali A, Lindtjorn B. Ownership and use of long-lasting insecticidal nets for malaria prevention in Butajira area, south-central Ethiopia: complex samples data analysis. BMC public health 2014; 14: 99.

Woyessa A, Deressa W, Ali A, Lindtjørn B. Evaluation of CareStartTM malaria Pf/Pv combo test for Plasmodium falciparum and Plasmodium vivax malaria diagnosis in Butajira area, south-central Ethiopia. Malaria Journal 2013, 12:218 doi:10.1186/1475-2875-12-218

Woyessa A, Deressa W, Ali A, Lindtjørn B. Malaria risk factors in Butajira area, south-central Ethiopia: a multilevel analysis. Malaria Journal 2013, 12:273. 

Woyessa A, Deressa W, Ali A, Lindtjørn B. Prevalence of malaria infection in Butajira area, south-central Ethiopia. Malaria Journal 2012, 11:84

The full-text thesis can be downloaded here.