The national distribution of lymphatic filariasis cases in Malawi using patient mapping and geostatistical modelling.

BACKGROUND: In 2020 the World Health Organization (WHO) declared that Malawi had successfully eliminated lymphatic filariasis (LF) as a public health problem. Understanding clinical case distributions at a national and sub-national level is important, so essential care packages can be provided to individuals living with LF symptoms. This study aimed to develop a national database and map of LF clinical cases across Malawi using geostatistical modelling approaches, programme-identified clinical cases, antigenaemia prevalence and climate information. METHODOLOGY: LF clinical cases identified through programme house-to-house surveys across 90 sub-district administrative boundaries (Traditional Authority (TA)) and antigenaemia prevalence from 57 sampled villages in Malawi were used in a two-step geostatistical modelling process to predict LF clinical cases across all TAs of the country. First, we modelled antigenaemia prevalence in relation to climate covariates to predict nationwide antigenaemia prevalence. Second, we modelled clinical cases for unmapped TAs based on our antigenaemia prevalence spatial estimates. PRINCIPLE FINDINGS: The models estimated 20,938 (95% CrI 18,091 to 24,071) clinical cases in unmapped TAs (70.3%) in addition to the 8,856 (29.7%), programme-identified cases in mapped TAs. In total, the overall national number of LF clinical cases was estimated to be 29,794 (95% CrI 26,957 to 32,927). The antigenaemia prevalence and clinical case mapping and modelling found the highest burden of disease in Chikwawa and Nsanje districts in the Southern Region and Karonga district in the Northern Region of the country. CONCLUSIONS: The models presented in this study have facilitated the development of the first national LF clinical case database and map in Malawi, the first endemic country in sub-Saharan Africa. It highlights the value of using existing LF antigenaemia prevalence and clinical case data together with modelling approaches to produce estimates that may be used for the WHO dossier requirements, to help target limited resources and implement long-term health strategies.

Significant improvement in quality of life following surgery for hydrocoele caused by lymphatic filariasis in Malawi: A prospective cohort study.

BACKGROUND: Lymphatic filariasis (LF) is a mosquito-borne parasitic infection that causes significant disabling and disfiguring clinical manifestations. Hydrocoele (scrotal swelling) is the most common clinical condition, which affects an estimated 25 million men globally. The recommended strategy is surgical intervention, yet little is known about the impact of hydrocoele on men's lives, and how it may change if they have access to surgery. METHODOLOGY/PRINCIPAL FINDINGS: We prospectively recruited and followed-up men who underwent surgery for hydrocoele at six hospitals in an LF endemic area of Malawi in December 2015. Men were interviewed at hospitals pre-surgery and followed-up at 3-months and 6-months post-surgery. Data on demographic characteristics, clinical condition, barriers to surgery, post-surgery symptoms/complications and quality of life indicators were collected and analysed pre- and post-surgery, by age group and stage of disease (mild/moderate vs. severe), using chi-square tests and student's t test (paired). 201 men were interviewed pre-surgery, 152 at 3-months and 137 at 6-months post-surgery. Most men had unilateral hydrocoeles (65.2%), mild/moderate stages (57.7%) with an average duration of 11.4 years. The most reported cause of hydrocoele was it being sexually transmitted (22.4%), and the main barrier to surgery was the cost (36.3%). Pre-surgery, a significant difference in the scrotum side affected was found by age group (X2 = 5.978, p = 0.05), and men with severe stage hydrocoele reported more problems with their quality of life than those with mild/moderate stage (t = 2.793; p = 0.0006). Post-surgery, around half of the men reported some pain/discomfort (55.9%), swelling (8.6%), bleeding (3.3%) and infection (5.9%), most of which had resolved at 3-months when the most significant improvements in their quality of life were found (t = 21.3902; p = 0.000). Post-surgery at 6 months all men reported no physical, social, psychological problems and took no time off work. CONCLUSION/SIGNIFICANCE: Surgery had a significant positive impact on many aspects of a patient's life, and the expansion of this treatment to all those affected in LF endemic areas would greatly improve the quality of men's and their families' lives, and greatly contribute to the global goal of providing universal health care.

Measuring the physical and economic impact of filarial lymphoedema in Chikwawa district, Malawi: a case-control study.

BACKGROUND: Lymphatic filariasis (LF) is one of the primary causes of lymphoedema in sub-Saharan Africa, and has a significant impact on the quality of life (QoL) of those affected. In this paper we assess the relative impact of lymphoedema on mobility and income in Chikwawa district, Malawi. METHODS: A random sample of 31 people with lymphoedema and 31 matched controls completed a QoL questionnaire from which both an overall and a mobility-specific score were calculated. Two mobility tests were undertaken, namely the 10 m walking test [10MWT] and timed up and go [TUG] test, and a subset of 10 cases-control pairs wore GPS data loggers for 3 weeks to measure their mobility in a more natural setting. Retrospective economic data was collected from all 31 case-control pairs, and each participant undertaking the GPS activity recorded daily earnings and health expenditure throughout the observation period. RESULTS: Cases had a significantly poorer overall QoL (cases = 32.2, controls = 6.0, P < 0.01) and mobility-specific (cases = 43.1, controls = 7.4, P < 0.01) scores in comparison to controls. Cases were also significantly slower (P < 0.01) at completing the timed mobility tests, e.g. mean 10MWT speed of 0.83 m/s in comparison to 1.10 m/s for controls. An inconsistent relationship was observed between mobility-specific QoL scores and the timed test results for cases (10MWT correlation = -0.06, 95% CI = (-0.41, 0.30)), indicating that their perceived disability differed from their measured disability, whereas the results were consistent for controls (10MWT correlation = -0.61, 95% CI = (-0.79, -0.34)). GPS summaries indicated that cases generally walk shorter distances at slower speeds than control, covering a smaller geographical area (median area by kernel smoothing: cases = 1.25 km2, controls = 2.10 km2, P = 0.16). Cases reported earning less than half that earned by controls per week (cases = $0.70, controls = $1.86, P = 0.064), with a smaller proportion of their earnings (16% vs 22%, P = 0.461) being spent on healthcare. CONCLUSIONS: Those affected by lymphoedema are at a clear disadvantage to their unaffected peers, experiencing a lower QoL as confirmed by both subjective and objective mobility measures, and lower income. This study also indicates that objective measures of mobility may be a useful supplement to self-assessed QoL questionnaires when assessing the future impact of lymphoedema management interventions.