Comparison of standard and modified human landing catching techniques for blackfly collection

BACKGROUND

Human landing catches (HLCs) are required to collect blackflies for entomological evaluation to verify onchocerciasis elimination. However, there are ethical concerns regarding exposure of vector collectors to infectious blackflies and safer alternative methods are needed. This study evaluated a modified HLC technique where collectors wore coloured trousers (blue, black or blue-black), protecting them from bites during fly collection, and their performance was compared with the standard.

METHODS

The study was conducted in Makouopsap, Cameroon, in the Massangam health district for 4 months. Four collector pairs-one 'standard' (bare-legged) and three modified-were placed 50 m apart along known breeding sites on the Mbam and Nja Rivers. Collections were performed from 07:00 to 17:00 h, 4 d/month. Hourly rates of flies caught were analysed using a negative binomial generalised linear model to explore associations between flies caught and collection techniques and seasons.

RESULTS

Overall, 17 246 blackflies were caught. There was no significant statistical difference in the number of blackflies and parous flies caught between black trousers and the standard. Thus there is a strong indication that wearing black trousers is a viable non-inferior alternative to the standard HLC.

CONCLUSIONS

Further studies are needed to confirm generalisability in different ecozones and transmission environments and among different blackfly species.

Correction: Ivermectin and doxycycline treatments against Onchocerciasis: Adaptations and impact among semi-nomadic population in Massangam Health District, Cameroon

[This corrects the article DOI: 10.1371/journal.pntd.0011463.].

Cost of implementing a doxycycline test-and-treat strategy for onchocerciasis elimination among settled and semi-nomadic groups in Cameroon

BACKGROUND

Onchocerciasis is a neglected tropical disease with 217.5 million people globally at risk of having the infection. In both settled and semi-nomadic communities of Massangam Health District in Cameroon, Sightsavers has been carrying out test-and-treat with doxycycline and twice-yearly ivermectin distribution. This paper focuses on the cost of test-and-treat with doxycycline in the two community contexts of settled and semi-nomadic.

METHODS

For the valuation, a combination of gross or micro-costing was used to identify cost components, as well as bottom-up and top-down approaches. The opportunity costs of vehicle and equipment use were estimated and included. Not included, however, were the opportunity costs of building use and Ministry of Public Health staff salaries. We only captured the incremental costs of implementing test-and-treat activities as part of a functional annual community-directed treatment with the ivermectin programme.

RESULTS

We estimate the economic cost per person tested and cost per person treated in Massangam to be US$135 and US$667 respectively. Total implementation cost in the settled community was US$79,409, and in the semi-nomadic community US$69,957. Overall, the total economic cost of implementing the doxycycline test-and-treat strategy for onchocerciasis elimination in Massangam came to US$168,345. Financial costs represented 91% of total costs.

CONCLUSIONS

Unit costs of test-and-treat in both settled and semi-nomadic communities are higher than unit costs of community-directed treatment with ivermectin. However, it is critical to note that a two-year implementation shows a significantly larger reduction in infection prevalence than the preceding 20 years of annual community-directed treatment with ivermectin. Test-and-treat with doxycycline may be a cost-effective intervention in places where the prevalence of microfilaria is still high, or in hard-to-reach areas where community-directed treatment with ivermectin and MDA coverage are not high enough to stop transmission or where marginalised populations consistently miss treatment.

Ivermectin and doxycycline treatments against Onchocerciasis: Adaptations and impact among semi-nomadic population in Massangam Health District, Cameroon

We trialed strategies to reach semi-nomadic population with interventions targeting onchocerciasis including a combination of community knowledge and Geographical Information System (GIS) technology; nomad-specific sensitization; and mobile outreach. The interventions included ivermectin (ivm) mass drug administration (MDA) and treating infected individuals (found upon skin snip microscopy test) with doxycycline for 35 days. Microscopy-negative snips were further tested by Polymerase Chain Reaction (PCR). After 8 months, individuals immigrating or emigrating constituted 47% of the initial population; 59% of individuals not born in the area have immigrated during the last five years; 28% (age>9) reportedly never taken ivm; 72% (compared to 51% previously) of eligible population (age ≥ 5 years) took ivm; and 47% (age > 8, not pregnant, not breastfeeding, not severely ill,) participated in the test. A high prevalence of onchocerciasis,15.1%, was found upon microscopy & PCR test; 9/10 tested by skin snip microscopy and PCR at follow-up were all negative. Microfilaria prevalence and intensity upon skin snip microscopy reduced significantly from baseline following the intervention (8.9% to 4.1%, p = 0.032; 0.18 to 0.16, p = 0.013, respectively). The strategies considerably increased reach to nomadic camps. Treating with doxycycline in combination with ivm is feasible and has led to a significant reduction in infection level within one year among the semi-nomads. Being potentially curative in one intervention round, this combination should be considered for population group faced with challenges of achieving adequate coverage and adhesion to ivm MDA over prolonged period (>10 years).

Acceptability of test and treat with doxycycline against Onchocerciasis in an area of persistent transmission in Massangam Health District, Cameroon

The main onchocerciasis elimination strategy is annual Community-Directed Treatment with ivermectin (CDTi). However, as a response to persistent high infection prevalence in Massangam Health District in Cameroon, two rounds of alternative treatments including biannual CDTi, ground larviciding and test and treat with doxycycline (TTd) were implemented. This led to a significant prevalence reduction from 35.7% to 12.3% (p<0.001) as reported by Atekem and colleagues. Here we report on the acceptability of TTd component based on qualitative and quantitative data. The TTd involved microscopic examination for microfilaria in skin biopsy and those infected were offered doxycycline 100 mg daily for 35 days by community-directed distributors (CDDs). Participation level was significantly high with 54% of eligible population (age > 8, not pregnant, not breastfeeding, not severely ill,) participating in the test in each round, increasing to 83% over the two rounds. Factors associated with non-participation included mistrust, being female; being younger than 26 years; short stay in the community; and belonging to semi-nomadic sub population due to their remote and disperse settlement, discrimination, their non selection as CDD, and language and cultural barriers. Treatment coverage was high -71% in round 1 and 83% in round 2. People moving away between testing and treatment impacted treatment coverage. Some participants noted mismatch between symptoms and test result; and that ivermectin is better than doxycycline, while others favoured doxycycline. CDD worried about work burden with unmatching compensation. Overall, TTd participation was satisfactory. But can be improved through reinforcing sensitisation, reducing time between test and treatment; combining TTd and CDTi in one outing; augmenting CDDs compensation and/or weekly visit; exploring for frequently excluded populations and adapting strategies to reach them; and use of a sensitive less invasive test.

Reach and Utility of COVID-19 Information and Preventive Measures for Nomadic Populations in Massangam, West Region of Cameroon

The separation of nomadic pastoralist settlements from settled communities is a well-known challenge to the health system. Difficulties reaching these groups contribute to inequities in their health and impact the spread or control of several diseases. COVID-19 has led to the suspension of many public health interventions in Cameroon, while preventive measures including behavior change communication have been ongoing since the onset of the pandemic. The reach and utility of these campaigns in semi-nomadic population remain unclear. This exploratory qualitative study was conducted in September to October 2020 using semi-structured interviews and focus group discussions with nomadic camp heads, and their wives to explore their interactions with communication campaigns, awareness, understanding, and acceptance of behavior change messages. The study revealed a general awareness of COVID-19 and its preventive measures and a prevailing belief that they were less at risk because their camps are isolated from the main communities, and the fact that they had never met a COVID-19 case. They perceived that the women were at lower risk because of their limited interaction outside the camps. There was a common concern regarding the transmission of COVID-19 to their cattle. Routes of communication were markets and mosques frequented by men, making access to information limited to or dependent on men. Financial constraints and lack of water were the main barriers affecting the access to and use of COVID-19 prevention measures. There is need for adaptive communication strategies especially tailored to the culture of nomadic pastoralists addressing gender dynamics of this subgroup.

Testing a method of sampling for entomological determination of transmission of Wuchereria bancrofti to inform lymphatic filariasis treatment strategy in urban settings

BACKGROUND

There is on-going debate about scale-up of lymphatic filariasis treatment to include urban areas. Determining Wuchereria bancrofti transmission is more complex in these settings and entomological methodologies suggested as a solution as yet have no clear guidance.

METHODS

The study was conducted in six communities in Minna and Kaduna cities in Nigeria selected based on pre-disposing risk factors for mosquitoes and Transmission Assessment Survey (TAS) results in 2016 indicating need for treatment (> 1% prevalence). In each community, 4 gravid traps (GT), 15 exit traps (ET) and 21 pyrethrum spray catches (PSC) were used for 5 months targeting a sample size of 10,000 mosquitoes inclusive of at least 1500 Anopheles. Community researchers were selected and trained to facilitate community acceptability and carry out collection. We have evaluated the mosquito sampling and trapping methodology in terms of success at reaching targeted sample size, cost effectiveness, and applicability.

RESULTS

Community researchers were influential in enabling high acceptability of the methods of collection and were able to conduct collections independently. Overall, 12.1% of trapping events (one trapping event corresponds to one visit to one trap to collect mosquitoes) were affected by householder actions, weather conditions or trap malfunction leading to lower than optimal catches. Exit traps were the most cost-effective way to catch Anopheles (6.4 USD per trapping event and 12.8 USD per Anopheles caught). Sample size of 10,000 mosquitoes overall in each city was met though Anopheles catch was insufficient in one city. However, sample size was met only in one implementation unit out of the four.

CONCLUSIONS

Methods need adapting to maximise Anopheles catch: we propose planning 250 gravid trap and 3724 exit trap trapping events in similar settings in West African urban areas where Culex is dominant, not using pyrethrum spray catches, and weighting trapping events later in the rainy season. Planning should increase involvement of community researchers, incorporate null catches and participants' actions to predict catches. Importantly, evaluation units should be analogous with implementation units, the units at which treatment decisions will be made in the urban context.

Research Ethics Committees (RECs) and epidemic response in low and middle income countries

The recent Ebola and Zika virus epidemics in some parts of Africa and Asia have showcased the porosity in disaster preparedness and response, not only in the affected countries, but on a global scale. For the Ebola epidemic, scientifically robust research was started late during the course of the epidemic, with waste of resources and lost research opportunities. Research Ethics Committees have a significant role to play with regards to epidemic response for the future. This paper presents key challenges and opportunities for ethics review during emergencies, specifically for low and middle income countries. There is no better moment to test the efficacy and safety of drugs or vaccines for infected, or at risk populations than during the disaster itself. The main mantras that form the back bone of research ethics review (Helsinki Declaration, the CIOMS International Ethical Guidelines for Biomedical Research Involving Human Subjects, WHO and the ICH guidelines for Good Clinical Practice) are increasingly showing their limitations. Most protocols are generally from developed countries where the funding originates. Not only is the direct transposition to Low and Middle Income Country (LMIC) settings inappropriate on its own, also, using such guidelines in times of public health disasters might be time consuming, and might also lead to wastage of research opportunities, especially when sociocultural peculiarities, and anthropological research arms are completely excluded or avoided within the care and research packages. Governments should include RECs as key members during the elaboration, and daily functioning of their national public emergency response packages. Developing simple research ethics review guidelines, involvement of health care staff in ethics training, community mobilization, and incorporation of anthropological research during the medical response, research and communication phases, are imperatives in epidemic response.

The spectrum of skin diseases in a rural setting in Cameroon (sub-Saharan Africa)

Background

Skin disorders are generally considered to be more prevalent in the rural areas of Cameroon. This study was carried out to verify this assumption by describing the spectrum of skin disorders in a rural setting of Cameroon.

Methods

We carried out a community-based clinical skin examination of 400 consenting subjects from 4 villages of Cameroon: Nyamanga (27%), Yebekolo (24%), Mbangassina (23%) and Bilomo (26%).

Results

The overall prevalence of skin diseases in our sample was 62% {95% CI: 57.2%, 66.8%} (248/400). The commonest skin disorders were: fungal infections (25.4%), parasitic infestations (21.4%), atrophic skin disorders (11.7%), hypertrophic skin disorders (9.7%), disorders of skin appendages {acne} (8.9%), benign neoplasm (6.5%), bacterial skin infections (5.2%), pigmentation disorders (4.8%), and dermatitis/eczema (4.0%). Skin infections and infestations constituted 52.82% of all skin disorders. The overall prevalence of infectious and parasitic infestation was 32.75% {95%CI: 28.17%, 37.59%} (131/400) as against 29.25% {95%CI: 24.83%, 33.98%} (117/400) for non-infectious disorders.

Among people with skin infections/parasitic infestations, those with fungal infections and onchocercal skin lesions were the most prevalent, accounting for 48.1% (63/131) and 35.1% (46/131); and an overall prevalence of 15.75% {95%CI: 12.3%, 19.7%} (63/400) and 11.5% {95%CI: 8.5%, 15.0%} (46/400) respectively.

There was secondary bacterial infection in 12.1% {95%CI: 8.31%, 16.82%} (30/248) of subjects with skin diseases. Hypertrophic and atrophic disorders of the skin were mainly keloids (9.68%), scarification marks (6.05%) and burn scars (5.65%). Skin diseases like dermatitis and eczema (4.03%), malignant tumours and pigmentation disorders were rare in our sample.

The proportion of subjects diagnosed with skin disorders after examination (62.8%) was significantly higher than the proportion of 40.8% that declared having skin diseases (p < 0.0001).

Conclusion

The prevalence of skin diseases in the rural Mbam valley is alarming, dominated by easily treatable or preventable skin infections and their magnitude is highly neglected by the community, contrasting with findings in the urban setting. Similar studies are needed in other ecological/demographic settings of the country in order to construct a better understanding of the epidemiology of skin disorders. This would lead to the development of national policies to improve skin care.