Rodent control strategies and Lassa virus: some unexpected effects in Guinea, West Africa

The Natal multimammate mouse (Mastomys natalensis) is the host of Lassa mammarenavirus, causing Lassa haemorrhagic fever in West Africa. As there is currently no operational vaccine and therapeutic drugs are limited, we explored rodent control as an alternative to prevent Lassa virus spillover in Upper Guinea, where the disease is highly endemic in rural areas. In a seven-year experiment, we distributed rodenticides for 10-30 days once a year and, in the last year, added intensive snap trapping for three months in all the houses of one village. We also captured rodents both before and after the intervention period to assess their effectiveness by examining alterations in trapping success and infection rates (Lassa virus RNA and IgG antibodies). We found that both interventions reduced the rodent population by 74-92% but swiftly rebounded to pre-treatment levels, even already six months after the last snap-trapping control. Furthermore, while we observed that chemical control modestly decreased Lassa virus infection rates annually (a reduction of 5% in seroprevalence per year), the intensive trapping unexpectedly led to a significantly higher infection rate (from a seroprevalence of 28% before to 67% after snap trapping control). After seven years, we conclude that annual chemical control, alone or with intensive trapping, is ineffective and sometimes counterproductive in preventing Lassa virus spillover in rural villages. These unexpected findings may result from density-dependent breeding compensation following culling and the survival of a small percentage of chronically infected rodents that may spread the virus to a new susceptible generation of mice.

Spatio-temporal spread of Lassa virus and a new rodent host in the Mano River Union area, West Africa

The spread of Lassa virus (LASV) in Guinea, Liberia and Sierra Leone, which together are named the Mano River Union (MRU) area, was examined phylogeographically. To provide a reliable evolutionary scenario, new rodent-derived, whole LASV sequences were included. These were generated by metatranscriptomic next-generation sequencing from rodents sampled between 2003 and 2020 in 21 localities of Guinea and Sierra Leone. An analysis was performed using BEAST to perform continuous phylogeographic inference and EvoLaps v36 to visualize spatio-temporal spread. LASV was identified as expected in its primary host reservoir, the Natal multimammate mouse (Mastomys natalensis), and also in two Guinean multimammate mice (Mastomys erythroleucus) in northern Sierra Leone and two rusty-bellied brush-furred mice (Lophuromys sikapusi) in southern Sierra Leone. This finding is consistent with the latter two species being secondary host reservoirs. The strains in these three species were very closely related in LASV lineage IV. Phylogenetic analysis indicated that the most recent common ancestor of lineage IV existed 316-374 years ago and revealed distinct, well-supported clades from Sierra Leone (Bo, Kabala and Kenema), Guinea (Faranah, Kissidougou-Guekedou and Macenta) and Liberia (Phebe-Ganta). The phylogeographic scenario suggests southern Guinea as the point of origin of LASV in the MRU area, with subsequent spread to towards Mali, Liberia and Sierra Leone at a mean speed of 1.6 to 1.1 km/year.

Circulation of Lassa virus across the endemic Edo-Ondo axis, Nigeria, with cross-species transmission between multimammate mice

We phylogenetically compared sequences of the zoonotic Lassa virus (LASV) obtained from Mastomys rodents in seven localities across the highly endemic Edo and Ondo States within Nigeria. Sequencing 1641 nt from the S segment of the virus genome, we resolved clades within lineage II that were either limited to Ebudin and Okhuesan in Edo state (2g-beta) or along Owo-Okeluse-Ifon in Ondo state (2g-gamma). We also found clades within Ekpoma, a relatively large cosmopolitan town in Edo state, that extended into other localities within Edo (2g-alpha) and Ondo (2g-delta). LASV variants from M. natalensis within Ebudin and Ekpoma in Edo State (dated approximately 1961) were more ancient compared to those from Ondo state (approximately 1977), suggesting a broadly east-west virus migration across south-western Nigeria; a pattern not always consistent with LASV sequences derived from humans in the same localities. Additionally, in Ebudin and Ekpoma, LASV sequences between M. natalensis and M. erythroleucus were interspersed on the phylogenetic tree, but those from M. erythroleucus were estimated to emerge more recently (approximately 2005). Overall, our results show that LASV amplification in certain localities (reaching a prevalence as high as 76% in Okeluse), anthropogenically-aided spread of rodent-borne variants amidst the larger towns (involving communal accommodation such as student hostels), and virus-exchange between syntopic M. natalensis and M. erythroleucus rodents (as the latter, a savanna species, encroaches southward into the degraded forest) pose perpetual zoonotic hazard across the Edo-Ondo Lassa fever belt, threatening to accelerate the dissemination of the virus into non endemic areas.

Prevalence of malaria resistance-associated mutations in Plasmodium falciparum circulating in 2017–2018, Bo, Sierra Leone

Introduction

In spite of promising medical, sociological, and engineering strategies and interventions to reduce the burden of disease, malaria remains a source of significant morbidity and mortality, especially among children in sub-Saharan Africa. In particular, progress in the development and administration of chemotherapeutic agents is threatened by evolved resistance to most of the antimalarials currently in use, including artemisinins.

Methods

This study analyzed the prevalence of mutations associated with antimalarial resistance in Plasmodium falciparum from 95 clinical samples collected from individuals with clinically confirmed malaria at a hospital in Bo, Sierra Leone between May 2017 and December 2018. The combination of polymerase chain reaction amplification and subsequent high throughput DNA sequencing was used to determine the presence of resistance-associated mutations in five P. falciparum genes – pfcrt, pfmdr1, pfdhfr, pfdhps and pfkelch13. The geographic origin of parasites was assigned using mitochondrial sequences.

Results

Relevant mutations were detected in the pfcrt (22%), pfmdr1 (>58%), pfdhfr (100%) and pfdhps (>80%) genes while no resistance-associated mutations were found in the pfkelch13 gene. The mitochondrial barcodes were consistent with a West African parasite origin with one exception indicating an isolate imported from East Africa.

Discussion

Detection of the pfmdr1 NFSND haplotype in 50% of the samples indicated the increasing prevalence of strains with elevated tolerance to artemeter + lumefantrine (AL) threatening the combination currently used to treat uncomplicated malaria in Sierra Leone. The frequency of mutations linked to resistance to antifolates suggests widespread resistance to the drug combination used for intermittent preventive treatment during pregnancy.

Detection of Lassa Virus-Reactive IgG Antibodies in Wild Rodents: Validation of a Capture Enzyme-Linked Immunological Assay

The aim of this study was to evaluate the use of a capture enzyme-linked immunosorbent assay (ELISA) for the detection of LASV-reactive IgG antibodies in Mastomys rodents. The assay was used for laboratory-bred Mastomys rodents, as well as for animals caught in the wild in various regions of West Africa. The ELISA reached an accuracy of 97.1% in samples of known exposure, and a comparison to an immunofluorescence assay (IFA) revealed a very strong agreement between the ELISA and IFA results (Cohen’s kappa of 0.81). The agreement is valid in Nigeria, and in Guinea and Sierra Leone where the lineages II and IV are circulating, respectively. Altogether, these results indicate that this capture ELISA is suitable for LASV IgG serostatus determination in Mastomys rodents as an alternative to IFA. This assay will be a strong, accurate, and semi-quantitative alternative for rodent seroprevalence studies that does not depend on biosafety level 4 infrastructures, providing great benefits for ecology and epidemiology studies of Lassa fever, a disease listed on the Research and Development Blueprint of the WHO.

Detection of Lassa virus in wild rodent feces: Implications for Lassa fever burden within households in the endemic region of Faranah, Guinea

Lassa arenavirus (LASV) is the cause of Lassa Fever in humans in West Africa. The multimammate mouse (Mastomys natalensis) is a reservoir host of LASV and the primary source of human infections. Humans are assumed to become infected due to contact with this animal or its excretions. Thus far, the available literature does not describe the sampling of feces as a means to detect LASV in M. natalensis populations. More evidence is needed to know if feces of naturally infected M. natalensis can be LASV-positive and an exposure risk to humans. This study sampled feces deposits in households from three villages in the LASV-endemic region of Faranah, Guinea. PCR analysis found 10 out of 88 samples to be positive for LASV, and sequencing showed clustering to previously identified Yarawelia and Dalafilani strains. We conclude that feces sampling is a viable, non-invasive method for the determination and sequencing of LASV strains.

Comparison of capillary and venous blood for malaria detection using two PCR-based assays in febrile patients in Sierra Leone

Background

Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sensitive with both materials, the published data on this subject are scarce and not conclusive.

Methods

Paired clinical samples of venous and capillary blood from 141 febrile individuals in Bo, Sierra Leone, were obtained between January and May 2019 and tested for the presence of Plasmodium parasites using two multiplexed PCR assays: the FilmArray-based Global Fever Panel (GFP) and the TaqMan-based Malaria Multiplex Sample Ready (MMSR) assay.

Results

No significant differences in Plasmodium parasite detection between capillary and venous blood for both assays were observed. The GFP assay was more sensitive than MMSR for all markers that could be compared (Plasmodium spp. and Plasmodium falciparum) in both venous and capillary blood.

Conclusions

No difference was found in malaria detection between venous and capillary blood using two different PCR-based detection assays. This data gives support for use of capillary blood, a material which can be obtained easier by less invasive methods, for PCR-based malaria diagnostics, independent of the platform.

Estimating the size of urban populations using Landsat images: a case study of Bo, Sierra Leone, West Africa

Background

This is the third paper in a 3-paper series evaluating alternative models for rapidly estimating neighborhood populations using limited survey data, augmented with aerial imagery.

Methods

Bayesian methods were used to sample the large solution space of candidate regression models for estimating population density.

Results

We accurately estimated the population densities and counts of 20 neighborhoods in the city of Bo, Sierra Leone, using statistical measures derived from Landsat multi-band satellite imagery. The best regression model proposed estimated the latter with an absolute median proportional error of 8.0%, while the total population of the 20 neighborhoods was estimated with an error of less than 1.0%. We also compare our results with those obtained using an empirical Bayes approach.

Conclusions

Our approach provides a rapid and effective method for constructing predictive models for population densities and counts utilizing remote sensing imagery. Our results, including cross-validation analysis, suggest that masking non-urban areas in the Landsat section images prior to computing the candidate covariate regressors should further improve model generality.

PO 8584 MULTIPLEXED MOLECULAR DETECTION OF MALARIA IN SIERRA LEONE

Background

Despite several control measures and policy changes in Africa, malaria remains one of the most prevalent diseases in West Africa. The gold standard for malaria diagnosis is microscopy. However, due to low technical capacities in resource-poor countries, rapid immunochromatographic tests are commonly used. In Sierra Leone, P. falciparum-specific ICT with histidine-rich proteins2(HRP-2) are used. HRP2 is specific to P. falciparum and the kit cannot be used to detect other species of malaria which are also present in the disease ecology in Sierra Leone.

Methods

In this study, we assessed 182 febrile subjects for malaria between April 2017-July 2018 at the Mercy Hospital Research Laboratory in Sierra Leone. The blood samples collected were assessed using the Walter Reed Army Institute for Research(WRAIR) multiplex malaria PCR kit packaged by BioGX, Inc. (Alabama, USA) for detecting and speciation of malaria from human blood. Thin and thick slides were done for each sample and the images recorded by a digital scope.

Results

Results show that, out of 163 samples run by multiplex PCR for malaria, 81 (49.7%) were positive for P. falciparum, while 82 (50.3%) were positive for Plasmodium vivax.

Conclusion

The presence of P. vivax in the disease ecology without any significant difference (p>0.05) with P. falciparum poses problems for clinical outcomes of febrile illnesses. Pan-malaria diagnostics in combination with P. falciparum could avert under-diagnosis of malaria.

Seroprevalence of hepatitis B surface antigen (HBsAg) in Bo, Sierra Leone, 2012-2013

OBJECTIVE

The aim of this study was to determine the prevalence of hepatitis B surface antigen (HBsAg) among febrile individuals tested at Mercy Hospital Research Laboratory (MHRL) in Bo, Sierra Leone.

RESULTS

A total of 860 febrile individuals ages 5 years and older were tested by MHRL between July 2012 and June 2013 with a Standard Diagnostics Bioline HBsAg rapid diagnostic test. The overall HBsAg prevalence rate was 13.7%, including a rate of 15.5% among males and 12.6% among females. The HBsAg rate did not differ by child or adult age group (p > 0.5). The prevalence rate in Bo was similar to the 11-15% HBsAg prevalence rates reported in the past decade from other studies across West Africa. Scaling up the infant hepatitis B vaccination program in Sierra Leone will be important for reducing the future burden of disease and premature death attributable to chronic viral hepatitis B disease.

Prevalence of markers of HIV infection among febrile adults and children in Bo, Sierra Leone, 2012-2013

OBJECTIVE

The goal of this study was to examine the prevalence of HIV among febrile patients seeking care in Mercy Hospital, Bo, Sierra Leone, in 2012-2013.

RESULTS

A total of 1207 febrile persons were tested for HIV with Determine™ and SD Bioline rapid diagnostic tests kits that detect the presence of HIV antibodies and HIV p24 antigens. The overall prevalence of HIV among the tested patients was 8.9%, which is considerably higher than the < 2% prevalence of HIV reported previously in the general population. While these results are not sufficient to prove a causal relationship, the obtained data imply that HIV positive individuals may be more likely to suffer from febrile infectious diseases than individuals without HIV infection. Increasing the availability and use of HIV testing services will allow antiretroviral therapy to be accessed in a timely manner and improve health status among people living with HIV.

Surveillance of Vector-Borne Infections (Chikungunya, Dengue, and Malaria) in Bo, Sierra Leone, 2012-2013

Malaria remains a significant cause of morbidity and mortality in West Africa, but the contribution of other vector-borne infections (VBIs) to the burden of disease has been understudied. We used rapid diagnostic tests (RDTs) for three VBIs to test blood samples from 1,795 febrile residents of Bo City, Sierra Leone, over a 1-year period in 2012-2013. In total, 24% of the tests were positive for malaria, fewer than 5% were positive for markers of dengue virus infection, and 39% were positive for IgM directed against chikungunya virus (CHIKV) or a related alphavirus. In total, more than half (55%) of these febrile individuals tested positive for at least one of the three VBIs, which highlights the very high burden of vector-borne diseases in this population. The prevalence of positives on the Chikungunya IgM and dengue tests did not vary significantly with age (P > 0.36), but higher rates of malaria were observed in children < 15 years of age (P < 0.001). Positive results on the Chikungunya IgM RDTs were moderately correlated with rainfall (r² = 0.599). Based on the high prevalence of positive results on the Chikungunya IgM RDTs from individuals Bo and its environs, there is a need to examine whether an ecological shift toward a greater burden from CHIKV or related alphaviruses is occurring in other parts of Sierra Leone or the West African region.

High prevalence of multidrug resistant Enterobacteriaceae isolated from outpatient urine samples but not the hospital environment in Bo, Sierra Leone

BACKGROUND

The rising level of antimicrobial resistance among bacterial pathogens is one of the most significant public health problems globally. While the antibiotic resistance of clinically important bacteria is closely tracked in many developed countries, the types and levels of resistance and multidrug resistance (MDR) among pathogens currently circulating in most countries of sub-Saharan Africa are virtually unknown.

METHODS

From December 2013 to April 2014, we collected 93 urine specimens from all outpatients showing symptoms of urinary tract infection (UTI) and 189 fomite swabs from a small hospital in Bo, Sierra Leone. Culture on chromogenic agar combined with biochemical and DNA sequence-based assays was used to detect and identify the bacterial isolates. Their antimicrobial susceptibilities were determined using a panel of 11 antibiotics or antibiotic combinations.

RESULTS

The 70 Enterobacteriaceae urine isolates were identified as Citrobacter freundii (n = 22), Klebsiella pneumoniae (n = 15), Enterobacter cloacae (n = 15), Escherichia coli (n = 13), Enterobacter sp./Leclercia sp. (n = 4) and Escherichia hermannii (n = 1). Antimicrobial susceptibility testing demonstrated that 85.7 % of these isolates were MDR while 64.3 % produced an extended-spectrum ß-lactamase (ESBL). The most notable observations included widespread resistance to sulphonamides (91.4 %), chloramphenicol (72.9 %), gentamycin (72.9 %), ampicillin with sulbactam (51.4 %) and ciprofloxacin (47.1 %) with C. freundii exhibiting the highest and E. coli the lowest prevalence of multidrug resistance. The environmental cultures resulted in only five Enterobacteriaceae isolates out of 189 collected with lower overall antibiotic resistance.

CONCLUSIONS

The surprisingly high proportion of C. freundii found in urine of patients with suspected UTI supports earlier findings of the growing role of this pathogen in UTIs in low-resource countries. The isolates of all analyzed species showed worryingly high levels of resistance to both first- and second-line antibiotics as well as a high frequency of MDR and ESBL phenotypes, which likely resulted from the lack of consistent antibiotic stewardship policies in Sierra Leone. Analysis of hospital environmental isolates however suggested that fomites in this naturally ventilated hospital were not a major reservoir for Enterobacteriaceae or antibiotic resistance determinants.

Inpatient healthcare provider bypassing by women and their children in urban Bo, Sierra Leone

Introduction

Bypassing refers to a person's decision to seek care at a healthcare facility that is not the nearest one of its type to the person's home.

Methods

This study examined inpatient care facility bypassing in urban Bo, Sierra Leone using data from 1,980 women with children 15 years of age and younger who were interviewed in 2010-2011. The locations of residential structures and hospitals were identified using a geographic information system (GIS), and the road distances from participating households to the nearest and preferred inpatient care facilities were measured.

Results

Nine inpatient care facilities serve Bo residents, but more than 70% of the participating women reported that the city's main public hospital (Bo Government Hospital), located in the city center, was their preferred inpatient care provider. Participants resided within a median distance of 0.9 km (Interquartile range (IQR): 0.6, 1.8) from their closest inpatient facility, but they would travel a median distance of 2.4 km (IQR: 1.0, 3.3) to reach their preferred providers. About 87% of the women would bypass their nearest inpatient care facility to access care at a preferred provider. Bypassing rates were similar for various demographic and socioeconomic groups, but higher for women living farther from the city center.

Conclusion

Although Bo has a diverse healthcare marketplace, access to affordable advanced care options is limited. Most women in Bo would choose to bypass facilities nearer to their homes to seek the low-cost and comprehensive care offered by Bo Government Hospital.

Child bed net use before, during, and after a bed net distribution campaign in Bo, Sierra Leone

BACKGROUND

This analysis examined how the proportion of children less than 5-years-old who slept under a bed net the previous night changed during and after a national long-lasting insecticidal net (LLIN) distribution campaign in Sierra Leone in November-December 2010.

METHODS

A citywide cross-sectional study in 2010-2011 interviewed the caregivers of more than 3000 under-five children from across urban Bo, Sierra Leone. Chi squared tests were used to assess change in use rates over time, and multivariate regression models were used to examine the factors associated with bed net use.

RESULTS

Reported rates of last-night bed net use changed from 38.7 % (504/1304) in the months before the LLIN campaign to 21.8 % (78/357) during the week of the campaign to 75.3 % (1045/1387) in the months after the national campaign. The bed net use rate significantly increased (p < 0.01) from before the campaign to after the universal LLIN distribution campaign in all demographic, socioeconomic, and health behaviour groups, even though reported use during the campaign dropped significantly.

CONCLUSION

Future malaria prevention efforts will need to promote consistent use of LLINs and address any remaining disparities in insecticide-treated bed net (ITN) use.

Stratified Sampling of Neighborhood Sections for Population Estimation: A Case Study of Bo City, Sierra Leone

There is a need for better estimators of population size in places that have undergone rapid growth and where collection of census data is difficult. We explored simulated estimates of urban population based on survey data from Bo, Sierra Leone, using two approaches: (1) stratified sampling from across 20 neighborhoods and (2) stratified single-stage cluster sampling of only four randomly-sampled neighborhoods. The stratification variables evaluated were (a) occupants per individual residence, (b) occupants per neighborhood, and (c) residential structures per neighborhood. For method (1), stratification variable (a) yielded the most accurate re-estimate of the current total population. Stratification variable (c), which can be estimated from aerial photography and zoning type verification, and variable (b), which could be ascertained by surveying a limited number of households, increased the accuracy of method (2). Small household-level surveys with appropriate sampling methods can yield reasonably accurate estimations of urban populations.

Herbs and herbal combinations used to treat suspected malaria in Bo, Sierra Leone

ETHNOPHARMACOLOGICAL RELEVANCE

Most adults in West Africa treat acute febrile illnesses with local herbs, but the patterns of herbs used for malaria have not been recently described in Sierra Leone.

MATERIALS AND METHODS

We used a population-based cross-sectional approach to interview 810 randomly-sampled rural and urban adult residents of Bo, Sierra Leone, in December 2013 and January 2014 about their use of herbal remedies when they suspect they have malaria.

RESULTS

In total, 55% of the participants reported taking one or more of seven herbs to treat symptoms of malaria. Among herb users, the most commonly used anti-malarial herbs were Moringa oleifera (moringa, 52%) and Sarcocephalus latifolius (yumbuyambay, 50%). The other herbs used included Senna siamea (shekutoure, 18%), Cassia sieberiana (gbangba, 18%), Uvaria afzelii (gone-botai, 14%), Morinda chrysorhiza (njasui, 14%), and Craterispermum laurinum (nyelleh, 7%). Combination herbal therapy was common, with 37% of herb users taking two or more herbs together when ill with suspected malaria.

CONCLUSIONS

Indigenous medical knowledge about herbal remedies and combinations of local herbs remains an integral part of malaria case management in Sierra Leone.

Attitudes toward home-based malaria testing in rural and urban Sierra Leone

Background

The purpose of this study was to examine malaria testing practices and preferences in Bo, Sierra Leone, and to ascertain interest in and willingness to take a home-based rapid diagnostic test administered by a community health volunteer (CHV) or a trained family member rather than travelling to a clinical facility for laboratory-based testing.

Methods

A population-based, cross-sectional survey of 667 randomly-sampled rural households and 157 urban households was conducted in December 2013 and January 2014.

Results

Among rural residents, 69% preferred a self/family- or CHV-conducted home-based malaria test and 20% preferred a laboratory-based test (with others indicating no preference). Among urban residents, these numbers were 38% and 44%, respectively. If offered a home-based test, 28% of rural residents would prefer a self/family-conducted test and 68% would prefer a CHV-assisted test. For urban residents, these numbers were 21% and 77%. In total, 36% of rural and 63% of urban residents reported usually taking a diagnostic test to confirm suspected malaria. The most common reasons for not seeking malaria testing were the cost of testing, waiting to see if the fever resolved on its own, and not wanting to travel to a clinical facility for a test. In total, 32% of rural and 27% of urban participants were very confident they could perform a malaria test on themselves or a family member without assistance, 50% of rural and 62% of urban participants were very confident they could perform a test after training, and 56% of rural and 33% of urban participants said they would pay more for a home-based test than a laboratory-based test.

Conclusion

Expanding community case management of malaria to include home testing by CHVs and family members may increase the proportion of individuals with febrile illnesses who confirm a positive diagnosis prior to initiating treatment.

Methods for determining the uncertainty of population estimates derived from satellite imagery and limited survey data: a case study of Bo city, Sierra Leone

This study demonstrates the use of bootstrap methods to estimate the total population of urban and periurban areas using satellite imagery and limited survey data. We conducted complete household surveys in 20 neighborhoods in the city of Bo, Sierra Leone, which collectively were home to 25,954 persons living in 1,979 residential structures. For five of those twenty sections, we quantized the rooftop areas of structures extracted from satellite images. We used bootstrap statistical methods to estimate the total population of the pooled sections, including the associated uncertainty intervals, as a function of sample size. Evaluations based either on rooftop area per person or on the mean number of occupants per residence both converged on the true population size. We demonstrate with this simulation that demographic surveys of a relatively small proportion of residences can provide a foundation for accurately estimating the total population in conjunction with aerial photographs.

Reemergence of chikungunya virus in Bo, Sierra Leone

We diagnosed 400 possible IgM-positive cases of chikungunya virus in Bo, Sierra Leone, during July 2012–January 2013 by using lateral flow immunoassays. Cases detected likely represent only a small fraction of total cases. Further laboratory testing is required to confirm this outbreak and characterize the virus.

Considerations in the selection of healthcare providers for mothers and children in Bo, Sierra Leone: reputation, cost and location

The factors that influence the selection of a healthcare provider once the decision to seek care has been made can be summarized using a triad of cost, location and reputation. The goal of this study was to identify which of these factors is the primary consideration when women in urban Bo, Sierra Leone, select a healthcare provider for themselves or their children. We interviewed 1091 mothers during a household census of two neighbourhoods of Bo in April 2010. Reputation was the top consideration for about half of the women, cost was the second most common priority, and the location of the healthcare facility was the primary consideration for less than 7% of the participants. The majority of women said they would select a new provider if cost was not a barrier. Socioeconomic characteristics were not significant predictors of whether cost, location or reputation was selected as the highest-ranked consideration. This evidence for the importance of reputation in healthcare decision-making even in low-resource areas highlights the need for health systems to address issues of quality and responsiveness, and not just cost, in order to increase access to and utilization of health services.

Multidrug-resistant tet(X)-containing hospital isolates in Sierra Leone

The tet(X) gene encodes a flavin-dependent monooxygenase that confers resistance to all clinically relevant tetracycline antibiotics including tigecycline. It has only previously been identified in environmental and non-human pathogenic bacteria. To investigate levels of multidrug resistance in Bo, Sierra Leone, a molecular epidemiological study was conducted using an antimicrobial resistance determinant microarray (ARDM), PCR and DNA sequencing. The study found that 21% of isolates from Mercy Hospital (Bo, Sierra Leone) were tet(X)-positive, all of which originated from urinary specimens. Use of molecular epidemiological surveillance tools has provided the first evidence of tet(X)-containing multidrug-resistant Gram-negative hospital isolates in a hospital in Sierra Leone.

Water quality associated public health risk in Bo, Sierra Leone

Human health depends on reliable access to safe drinking water, but in many developing countries only a limited number of wells and boreholes are available. Many of these water resources are contaminated with biological or chemical pollutants. The goal of this study was to examine water access and quality in urban Bo, Sierra Leone. A health census and community mapping project in one neighborhood in Bo identified the 36 water sources used by the community. A water sample was taken from each water source and tested for a variety of microbiological and physicochemical substances. Only 38.9% of the water sources met World Health Organization (WHO) microbial safety requirements based on fecal coliform levels. Physiochemical analysis indicated that the majority (91.7%) of the water sources met the requirements set by the WHO. In combination, 25% of these water resources met safe drinking water criteria. No variables associated with wells were statistically significant predictors of contamination. This study indicated that fecal contamination is the greatest health risk associated with drinking water. There is a need to raise hygiene awareness and implement inexpensive methods to reduce fecal contamination and improve drinking water safety in Bo, Sierra Leone.

Leapfrog diagnostics: Demonstration of a broad spectrum pathogen identification platform in a resource-limited setting

Background

Resource-limited tropical countries are home to numerous infectious pathogens of both human and zoonotic origin. A capability for early detection to allow rapid outbreak containment and prevent spread to non-endemic regions is severely impaired by inadequate diagnostic laboratory capacity, the absence of a “cold chain” and the lack of highly trained personnel. Building up detection capacity in these countries by direct replication of the systems existing in developed countries is not a feasible approach and instead requires “leapfrogging” to the deployment of the newest diagnostic systems that do not have the infrastructure requirements of systems used in developed countries.

Methods

A laboratory for molecular diagnostics of infectious agents was established in Bo, Sierra Leone with a hybrid solar/diesel/battery system to ensure stable power supply and a satellite modem to enable efficient communication. An array of room temperature stabilization and refrigeration technologies for reliable transport and storage of reagents and biological samples were also tested to ensure sustainable laboratory supplies for diagnostic assays.

Results

The laboratory demonstrated its operational proficiency by conducting an investigation of a suspected avian influenza outbreak at a commercial poultry farm at Bo using broad range resequencing microarrays and real time RT-PCR. The results of the investigation excluded influenza viruses as a possible cause of the outbreak and indicated a link between the outbreak and the presence of Klebsiella pneumoniae.

Conclusions

This study demonstrated that by application of a carefully selected set of technologies and sufficient personnel training, it is feasible to deploy and effectively use a broad-range infectious pathogen detection technology in a severely resource-limited setting.

Home birth and hospital birth trends in Bo, Sierra Leone

As of April 2010, all maternity care at government healthcare facilities in Sierra Leone is provided at no cost to patients. In late 2010, we conducted a community health census of 18 sections of the city of Bo (selected via randomized cluster sampling from 68 total sections). Among the 3421 women with a history of pregnancy who participated in the study, older women most often reported having a history of both home and hospital deliveries, while younger women showed a preference for hospital births. The proportion of lastborn children delivered at a healthcare facility increased from 71.8% of offspring 10-14 years old to 81.1% of those one to nine years old and 87.3% of infants born after April 2010. These findings suggest that the new maternal healthcare initiative has accelerated an existing trend toward a preference for healthcare facility births, at least in some urban parts of Sierra Leone.

Hypertension in Bo, Sierra Leone

OBJECTIVE

To identify the prevalence of hypertension among adults in Bo, Sierra Leone.

DESIGN

Hypertension data were extracted from outpatient clinic records.

SETTING

Mercy Hospital in urban Bo, Sierra Leone.

PATIENTS

All nonpregnant outpatients aged -15 years seen at the outpatient clinic in 2009.

MAIN OUTCOME MEASURES

Prevalence of hypertension, defined as a systolic blood pressure > or = 140 mm Hg and/or a diastolic blood pressure > or = 90 mm Hg.

RESULTS

Data from 3944 individuals were analyzed (mean age 38.7 years). The overall prevalence of hypertension among those aged > or = 15 years was 25.2%, with an age-adjusted prevalence of 19.6%. The prevalence of hypertension for participants aged > or = 20 years was 27.1%, with an age-adjusted prevalence of 23.6%. There were no significant differences in blood pressure by sex. The prevalence of hypertension increased significantly with age for both males and females (P < .001).

CONCLUSIONS

The prevalence of hypertension in Sierra Leone is consistent with the rates of hypertension observed in other parts of West Africa.

Enabling methods for community health mapping in developing countries

BACKGROUND

Spatial epidemiology is useful but difficult to apply in developing countries due to the low availability of digitized maps and address systems, accurate population distributions, and computational tools. A community-based mapping approach was used to demonstrate that participatory geographic information system (PGIS) techniques can provide information helpful for health and community development.

RESULTS

The PGIS process allowed for the rapid determination of sectional (neighborhood) boundaries within the city of Bo, Sierra Leone. When combined with data about hospital laboratory visits, a catchment area for one hospital in Bo could be established. A survey of households from within the catchment area determined that the average population per household (about 6 individuals) was similar to that found in the 2004 census. However, we also found that the average house was inhabited by more than one household, for an average of 17.5 inhabitants per residential building, which is critical information to know when estimating population size using remote imagery that can detect and enumerate buildings.

CONCLUSIONS

The methods developed in this paper serve as a model for the involvement of communities in the generation of municipal maps and their application to community and health concerns.