Brian Faragher

Snake envenoming: a disease of poverty.

Background Most epidemiological and clinical reports on snake envenoming focus on a single country and describe rural communities as being at greatest risk. Reports linking snakebite vulnerability to socioeconomic status are usually limited to anecdotal statements. The few reports with a global perspective have identified the tropical regions of Asia and Africa as suffering the highest levels of snakebite-induced mortality. Our analysis examined the association between globally available data on snakebite-induced mortality and socioeconomic indicators of poverty. Methodology/Principal Findings We acquired data on (i) the Human Development Index, (ii) the Per Capita Government Expenditure on Health, (iii) the Percentage Labour Force in Agriculture and (iv) Gross Domestic Product Per Capita from publicly available databases on the 138 countries for which snakebite-induced mortality rates have recently been estimated. The socioeconomic datasets were then plotted against the snakebite-induced mortality estimates (where both datasets were available) and the relationship determined. Each analysis illustrated a strong association between snakebite-induced mortality and poverty. Conclusions/Significance This study, the first of its kind, unequivocally demonstrates that snake envenoming is a disease of the poor. The negative association between snakebite deaths and government expenditure on health confirms that the burden of mortality is highest in those countries least able to deal with the considerable financial cost of snakebite.

Loss of endothelial protein C receptors links coagulation and inflammation to parasite sequestration in cerebral malaria in African children.

Cerebral malaria (CM) is a major cause of mortality in African children and the mechanisms underlying its development, namely how malaria-infected erythrocytes (IEs) cause disease and why the brain is preferentially affected, remain unclear. Brain microhemorrhages in CM suggest a clotting disorder, but whether this phenomenon is important in pathogenesis is debated. We hypothesized that localized cerebral microvascular thrombosis in CM is caused by a decreased expression of the anticoagulant and protective receptors thrombomodulin (TM) and endothelial protein C receptor (EPCR) and that low constitutive expression of these regulatory molecules in the brain make it particularly vulnerable. Autopsies from Malawian children with CM showed cerebral fibrin clots and loss of EPCR, colocalized with sequestered IEs. Using a novel assay to examine endothelial phenotype ex vivo using subcutaneous microvessels, we demonstrated that loss of EPCR and TM at sites of IE cytoadherence is detectible in nonfatal CM. In contrast, although clotting factor activation was seen in the blood of CM patients, this was compensated and did not disseminate. Because of the pleiotropic nature of EPCR and TM, these data implicate disruption of the endothelial protective properties at vulnerable sites and particularly in the brain, linking coagulation and inflammation with IE sequestration.

Macrofilaricidal Activity after Doxycycline Only Treatment of Onchocerca volvulus in an Area of Loa loa Co-Endemicity: A Randomized Controlled Trial

Background The risk of severe adverse events following treatment of onchocerciasis with ivermectin in areas co-endemic with loiasis currently compromises the development of control programmes and the treatment of co-infected individuals. We therefore assessed whether doxycycline treatment could be used without subsequent ivermectin administration to effectively deliver sustained effects on Onchocerca volvulus microfilaridermia and adult viability. Furthermore we assessed the safety of doxycycline treatment prior to ivermectin administration in a subset of onchocerciasis individuals co-infected with low to moderate intensities of Loa loa microfilaraemia. Methods A double-blind, randomized, field trial was conducted of 6 weeks of doxycycline (200 mg/day) alone, doxycycline in combination with ivermectin (150 µg/kg) at +4 months or placebo matching doxycycline + ivermectin at +4 months in 150 individuals infected with Onchocerca volvulus. A further 22 individuals infected with O. volvulus and low to moderate intensities of Loa loa infection were administered with a course of 6 weeks doxycycline with ivermectin at +4 months. Treatment efficacy was determined at 4, 12 and 21 months after the start of doxycycline treatment together with the frequency and severity of adverse events. Results One hundred and four (60.5%) participants completed all treatment allocations and follow up assessments over the 21-month trial period. At 12 months, doxycycline/ivermectin treated individuals had lower levels of microfilaridermia and higher frequency of amicrofilaridermia compared with ivermectin or doxycycline only groups. At 21 months, microfilaridermia in doxycycline/ivermectin and doxycycline only groups was significantly reduced compared to the ivermectin only group. 89% of the doxycycline/ivermectin group and 67% of the doxycycline only group were amicrofilaridermic, compared with 21% in the ivermectin only group. O. volvulus from doxycycline groups were depleted of Wolbachia and all embryonic stages in utero. Notably, the viability of female adult worms was significantly reduced in doxycycline treated groups and the macrofilaricidal and sterilising activity was unaffected by the addition of ivermectin. Treatment with doxycycline was well tolerated and the incidence of adverse event to doxycycline or ivermectin did not significantly deviate between treatment groups. Conclusions A six-week course of doxycycline delivers macrofilaricidal and sterilizing activities, which is not dependent upon co-administration of ivermectin. Doxycycline is well tolerated in patients co-infected with moderate intensities of L. loa microfilariae. Therefore, further trials are warranted to assess the safety and efficacy of doxycycline-based interventions to treat onchocerciasis in individuals at risk of serious adverse reactions to standard treatments due to the co-occurrence of high intensities of L. loa parasitaemias. The development of an anti-wolbachial treatment regime compatible with MDA control programmes could offer an alternative to the control of onchocerciasis in areas of co-endemicity with loiasis and at risk of severe adverse reactions to ivermectin. Trial Registration Controlled-Trials.com ISRCTN48118452

A Multi-Country Non-Inferiority Cluster Randomized Trial of Frontloaded Smear Microscopy for the Diagnosis of Pulmonary Tuberculosis

Luis Cuevas and colleagues report findings from a multicenter diagnostic clinical trial in tuberculosis, showing that the sensitivity and specificity of a “front-loaded” diagnostic scheme is not inferior to that of a standard diagnostic scheme.

Lack of decline in childhood malaria, Malawi, 2001-2010.

Despite increased control activities, malaria did not substantially decline.

Long term outcome of severe anaemia in Malawian children.

Background Severe anaemia is a common, frequently fatal, condition in African children admitted to hospital, but its long term outcome is unknown. Early reports that survivors may be at risk of additional late morbidity and mortality may have significant implications for child survival in Africa. We assessed the short and long term outcome of severe anaemia in Malawian children and identified potential risk factors for death and further severe anaemia. Methodology and Findings For 18 months, we followed up children (6–60 months old) presenting to hospital with severe anaemia (haemoglobin ≤5g/dl) and their hospital and community controls with the aim to compare all cause mortality and severe anaemia recurrence rates between the groups, and to identify risk factors for these adverse outcomes. A total of 377 cases, 377 hospital controls and 380 community controls were recruited. Among cases, the in-hospital mortality was 6.4% and post-discharge all cause mortality was 12.6%, which was significantly greater than in hospital controls (2.9%) or community controls (1.4%) (Log rank test, p<0.001). The incidence of recurrence of severe anaemia among the cases was 0.102 per child-year (95% Confidence Interval 0.075–0.138), and was significantly higher than the 0.007 per child-year (95% CI 0.003–0.015) in the combined controls (p<0.0001). HIV was the most important risk factor both for post-discharge mortality (Hazard Ratio 10.5, 95% CI 4.0–27.2) and for recurrence of severe anaemia (HR 5.6, 95% CI 1.6–20.1). Conclusions Severe anaemia carries a high ‘hidden’ morbidity and mortality occurring in the months after initial diagnosis and treatment. Because severe anaemia is very common, this is likely to contribute importantly to overall under-five mortality. If not adequately addressed, severe anaemia may be an obstacle to achievement of the Millennium development goal No.4 on child survival. Strategies to diagnose and properly treat HIV infected children early most likely will reduce the high post-discharge mortality in severe anaemia.

LED Fluorescence Microscopy for the Diagnosis of Pulmonary Tuberculosis: A Multi-Country Cross-Sectional Evaluation

This study, nested within a clinical trial, by Luis Cuevas and colleagues finds that LED-FM microscopy has higher sensitivity but lower specificity than Zn microscopy for detecting tuberculosis in sputum samples.

Long term impact of large scale community-directed delivery of doxycycline for the treatment of onchocerciasis

BackgroundAnti-Wolbachia treatment with doxycycline is effective in sterilising and killing adult Onchocerca volvulus nematodes, proving superior to ivermectin and of great potential as an alternative approach for the treatment and control of onchocerciasis, particularly in areas of Loa loa co-endemicity. Nevertheless, the length of the required treatment poses potential logistical problems and risk of poor compliance, raising a barrier to the use of doxycycline in Mass Drug Administration (MDA) strategies. In 2007 and 2008 a feasibility trial of community-directed treatment with doxycycline was carried out in two health districts in Cameroon, co-endemic for O. volvulus and L. loa. With 17,519 eligible subjects, the therapeutic coverage was 73.8% with 97.5% compliance, encouraging the feasibility of using doxycycline community-directed delivery in restricted populations of this size. The current study evaluated the effectiveness of this community-directed delivery of doxycycline four years after delivery.FindingsInfection with O. volvulus was evaluated by skin biopsy and nodule palpation. Of the 507 subjects recruited, 375 had completed the treatment with doxycycline followed by one or two rounds of annual ivermectin MDA and 132 received one or two rounds of annual ivermectin MDA alone. Statistically significant lower microfilarial prevalence (17.0% [doxycycline plus ivermectin group], 27.0% [ivermectin only group], p = 0.014) and load (p = 0.012) were found in people that had received doxycycline followed by ivermectin compared to those who received ivermectin only.ConclusionsThis study demonstrates the long-term effectiveness of doxycycline treatment delivered with a community-directed strategy even when evaluated four years after delivery in an area of ongoing transmission. This finding shows that a multi-week course of treatment is not a barrier to community-delivery of MDA in restricted populations of this size and supports its implementation to compliment existing control strategies for onchocerciasis, where needed.

Favourable one-year ART outcomes in adult Malawians with hepatitis B and C co-infection

BACKGROUND Few studies have investigated the impact of chronic hepatitis B and C infection on antiretroviral therapy (ART) outcomes in sub-Saharan Africa. Hepatotoxicity may be a particular concern in co-infected patients taking nevirapine-stavudine-lamivudine. METHODS We conducted a prospective cohort study of 300 Malawian adults starting ART and describe one-year ART outcomes according to viral hepatitis status. RESULTS At baseline, patients had advanced HIV disease (29.3% were in WHO stage 4; mean CD4 = 157 cells/microL; mean log(10)HIV-1 RNA = 5.24 copies/ml). Co-infection with hepatitis B, C and B + C were present in 6.7%, 5.7% and 1.7% respectively. At 50 weeks, all-cause mortality was 43 (14.3%). Sixteen (5.3%) had transferred to another unit. Eight (2.7%) were lost to follow up. Sixteen (5.3%) had stopped ART. 217 (72.3%) were alive on ART, of whom 82.5% had an HIV-1 RNA <400 copies/ml at week 50. During the first 50 weeks of ART, severe hepatotoxicity (liver enzyme values >5 times upper level of normal) occurred in 9%, but did not result in any ART discontinuations. Clinical hepatitis or jaundice was not observed. There were no significant differences in occurrence of hepatotoxicity, other side effects, mortality, severe morbidity, immune reconstitution or virological failure between hepatitis B and/or C co-infected patients and those who were not. Viral hepatitis co-infection was not associated with severe hepatotoxicity, mortality, severe morbidity or virological failure in multivariate analyses. CONCLUSION Our data suggest that screening for viral hepatitis B and C and liver enzyme monitoring may not require high priority in ART programmes in sub-Saharan Africa.

HIV, antiretroviral treatment, hypertension, and stroke in Malawian adults A case-control study

Objective: To investigate HIV, its treatment, and hypertension as stroke risk factors in Malawian adults. Methods: We performed a case-control study of 222 adults with acute stroke, confirmed by MRI in 86%, and 503 population controls, frequency-matched for age, sex, and place of residence, using Global Positioning System for random selection. Multivariate logistic regression models were used for case-control comparisons. Results: HIV infection (population attributable fraction [PAF] 15%) and hypertension (PAF 46%) were strongly linked to stroke. HIV was the predominant risk factor for young stroke (≤45 years), with a prevalence of 67% and an adjusted odds ratio (aOR) (95% confidence interval) of 5.57 (2.43–12.8) (PAF 42%). There was an increased risk of a stroke in patients with untreated HIV infection (aOR 4.48 [2.44–8.24], p < 0.001), but the highest risk was in the first 6 months after starting antiretroviral therapy (ART) (aOR 15.6 [4.21–46.6], p < 0.001); this group had a lower median CD4+ T-lymphocyte count (92 vs 375 cells/mm3, p = 0.004). In older participants (HIV prevalence 17%), HIV was associated with stroke, but with a lower PAF than hypertension (5% vs 68%). There was no interaction between HIV and hypertension on stroke risk. Conclusions: In a population with high HIV prevalence, where stroke incidence is increasing, we have shown that HIV is an important risk factor. Early ART use in immunosuppressed patients poses an additional and potentially treatable stroke risk. Immune reconstitution inflammatory syndrome may be contributing to the disease mechanisms.