Community based distribution of ivermectin in eastern Sudan: acceptability and early post-treatment reactions

The Galabat-Metema cross-border onchocerciasis focus: The first coordinated interruption of onchocerciasis transmission in Africa

Background

Onchocerciasis transmission across international borders is not uncommon, yet a coordinated cross border stops mass drug administration (MDA) decision has not been documented.

Methods/Principle findings

The Galabat-Metema focus involves neighboring districts on the border between Sudan and Ethiopia. Mass drug administration (MDA) was provided once and subsequently twice per year in this focus, with twice-per-year beginning in Ethiopia’s Metema subfocus in 2016 and in the Sudan’s Galabat subfocus in 2008. Ov16 ELISA-based serosurveys were conducted in 6072 children under 10 years of age in the Metema subfocus in 2014, and 3931 in the Galabat in 2015. Between 2014 and 2016, a total of 27,583 vector Simulium damnosum flies from Metema and 9,148 flies from Galabat were tested by pool screen PCR for Onchocerca volvulus O-150 DNA. Only 8 children were Ov16 seropositive (all in the Metema subfocus); all were negative by skin snip PCR. The upper limit of the 95% confidence interval (UCL) for Ov16 seropositive was <0.1% for the overall focus and 0.14 positive fly heads per 2000 (UCL = 0.39/2000). However, an entomological ‘hotspot’ was detected on the Wudi Gemzu river in Metema district. The hotspot was confirmed when 4 more positive fly pools were found on repeat testing in 2017 (1.04 L3/2000 flies (UCL = 2.26/2000). Information exchange between the two countries led to stopping MDA in a coordinated fashion in 2018, with the exception of the hotspot at Wudi Gemzu, where MDA with ivermectin was increased to every three months to hasten interruption of transmission.

Conclusion

Coordinated stop MDA decisions were made by Sudan and Ethiopia based on data satisfying the World Health Organization’s criteria for interruption of onchocerciasis transmission. Definitions of entomological ‘hotspots’ and buffer zones around the focus are proposed.

Onchocerciasis is a vector-borne tropical disease caused by the parasitc worm, Onchocerca volvulus. The vector is Simulium flies that breed in fast flowing rivers and streams. The infection can cause skin disease and loss of vision, giving risk to the common name of ‘river blindness’ for the condition. Ivermectin (Mectizan) mass drug administration (MDA) given at high coverage for many years can interrupt transmission such that MDA can eventually be stopped. The present paper provides highlights of onchocerciasis transmission interruption in the first known coordinated international cross border focus with ivermectin MDA program in Africa, where 99% of the global onchocerciasis burden exists. This focus known as Galabat-Metema is shared between Ethiopia and Sudan, both of which have established a nationwide policy for elimination of onchocerciasis. The paper provides the history of MDA in the border area and the results leading a coordinated end to MDA in the focus in 2017.

A Test-and-Not-Treat Strategy for Onchocerciasis in Loa loa-Endemic Areas

BACKGROUND

Implementation of an ivermectin-based community treatment strategy for the elimination of onchocerciasis or lymphatic filariasis has been delayed in Central Africa because of the occurrence of serious adverse events, including death, in persons with high levels of circulating Loa loa microfilariae. The LoaScope, a field-friendly diagnostic tool to quantify L. loa microfilariae in peripheral blood, enables rapid, point-of-care identification of persons at risk for serious adverse events.

METHODS

A test-and-not-treat strategy was used in the approach to ivermectin treatment in the Okola health district in Cameroon, where the distribution of ivermectin was halted in 1999 after the occurrence of fatal events related to L. loa infection. The LoaScope was used to identify persons with an L. loa microfilarial density greater than 20,000 microfilariae per milliliter of blood, who were considered to be at risk for serious adverse events, and exclude them from ivermectin distribution. Active surveillance for posttreatment adverse events was performed daily for 6 days.

RESULTS

From August through October 2015, a total of 16,259 of 22,842 persons 5 years of age or older (71.2% of the target population) were tested for L. loa microfilaremia. Among the participants who underwent testing, a total of 15,522 (95.5%) received ivermectin, 340 (2.1%) were excluded from ivermectin distribution because of an L. loa microfilarial density above the risk threshold, and 397 (2.4%) were excluded because of pregnancy or illness. No serious adverse events were observed. Nonserious adverse events were recorded in 934 participants, most of whom (67.5%) had no detectable L. loa microfilariae.

CONCLUSIONS

The LoaScope-based test-and-not-treat strategy enabled the reimplementation of community-wide ivermectin distribution in a heretofore "off limits" health district in Cameroon and is a potentially practical approach to larger-scale ivermectin treatment for lymphatic filariasis and onchocerciasis in areas where L. loa infection is endemic. (Funded by the Bill and Melinda Gates Foundation and others.).

Adverse reactions to the ivermectin treatment of onchocerciasis patients: does infection with the human immunodeficiency virus play a role?

To assess and compare the adverse effects resulting from ivermectin treatment of onchocerciasis patients with and without infection with human immunodeficiency virus (HIV-1), 1256 Ugandan cases of onchocerciasis were investigated as they were treated for the first time with the drug. Treatment followed the protocol of the Mectizan Expert Committee (i.e. a single dose of 150 mug/kg body weight). Adverse reactions to the ivermectin were determined, within 48 h of treatment, through questioning and clinical examinations during house-to-house visits. The HIV-1 status of each patient aged >15 years was initially determined using indirect ELISA, and any ELISA-positives were then confirmed in a western-blot assay. Among the cases aged >15 years, the frequency of adverse reactions to ivermectin was higher among those seropositive for HIV-1 (53.4%) than among the seronegative (45.7%) but the difference was not statistically significant (P = 0.25). The severity of the adverse reactions observed was, however, significantly lower in the HIV-1-positive patients than in the seronegative patients, with median scores of 1.37 and 1.68, respectively (P = 0.044). The conclusion is that ivermectin can be safely used for mass treatment in areas where the prevalences of onchocerciasis and HIV-1 infection are both high.

Nodding syndrome in Mundri county, South Sudan: environmental, nutritional and infectious factors

BACKGROUND

Nodding Syndrome is a seizure disorder of children in Mundri County, Western Equatoria, South Sudan. The disorder is reported to be spreading in South Sudan and northern Uganda.

OBJECTIVE

To describe environmental, nutritional, infectious, and other factors that existed before and during the de novo 1991 appearance and subsequent increase in cases through 2001.

METHODS

Household surveys, informant interviews, and case-control studies conducted in Lui town and Amadi village in 2001-2002 were supplemented in 2012 by informant interviews in Lui and Juba, South Sudan.

RESULTS

Nodding Syndrome was associated with Onchocerca volvulus and Mansonella perstans infections, with food use of a variety of sorghum (serena) introduced as part of an emergency relief program, and was inversely associated with a history of measles infection. There was no evidence to suggest exposure to a manmade neurotoxic pollutant or chemical agent, other than chemically dressed seed intended for planting but used for food. Food use of cyanogenic plants was documented, and exposure to fungal contaminants could not be excluded.

CONCLUSION

Nodding Syndrome in South Sudan has an unknown etiology. Further research is recommended on the association of Nodding Syndrome with onchocerciasis/mansonelliasis and neurotoxins in plant materials used for food.

Prevalences of loiasis in Ondo state, Nigeria, as evaluated by the rapid assessment procedure for loiasis (RAPLOA)

The rapid assessment procedure for loiasis (RAPLOA) was used to assess the prevalences of loiasis among 4800 subjects in 60 villages in Ondo state, south-western Nigeria. Coverages for community-directed treatment with ivermectin (CDTI) were assessed in the same communities, which were located in the Owo, Akure North, Ifedore, Akure South, Ondo East and Ondo West local government areas (LGA). In addition, fingerprick blood samples were collected from 80 individuals in each of six villages (i.e. one village in each LGA investigated) and checked for Loa loa microfilaraemia. Microfilaraemias were only detected in three of the villages where blood samples were collected and then only at low prevalences (1.25%-5.0%) and intensities (267-1600 microfilariae/ml). No serious adverse events were or ever had been related to the CDTI but mild or moderate adverse reactions were quite common, especially in Akure North (55.0%) and Owo (40.2%). A female subject was more likely to report an history of eye worm than a male subject (20.3%-35.7% v. 20.8%-26.5%, according to LGA). Although the subjects aged 41-50 years formed the age-group most likely to report an history of eye worm (32.7%), the highest CDTI coverage was recorded in the subjects aged 61-70 years (54.7%). The results indicated that CDTI had helped to reduce the prevalence and intensity of Loa microfilaraemia and that ivermectin can continue to be used for mass administrations in Ondo state with little risk of serious adverse events.

A randomized, double-blind, controlled trial of the effects of ivermectin at normal and high doses, given annually or three-monthly, against Onchocerca volvulus: ophthalmological results

A three-year randomized, controlled, double-blind trial was conducted in Cameroon to determine whether ivermectin, given at three-monthly intervals and/or at high doses (800 microg/kg), had a greater effect on adult Onchocerca volvulus than standard doses (150 microg/kg annually). As several patients complained of transitory subjective visual problems after treatment, some of them being of an unexpected type, we organized two series of detailed ophthalmological examinations to evaluate whether they were associated with ocular lesions. Analysis showed that these complaints were significantly more frequent in the two groups treated with high doses of ivermectin than in the reference group. In the ophthalmological examinations, the only differences recorded between the groups were a lower prevalence and mean number of microfilariae in the anterior chamber in the groups treated three-monthly, and, at the first examination round, a higher prevalence of early lesions of the iris in the group treated at high doses annually. These findings do not allow us to explain the cause of the transitory ocular complaints, nor why they were more frequent in the groups treated at high doses. However, one may conclude that using doses of ivermectin higher than the standard one should be considered with caution.

Adverse reactions following annual ivermectin treatment of onchocerciasis in Nigeria

OBJECTIVES

This study aims to document and underscore the need to monitor adverse reactions following repeated ivermectin treatment under the current dispensation of the implementation of the Community-directed Treatment with Ivermectin (CDTI) Program. As communities are empowered to distribute ivermectin, monitoring of adverse reactions by health care professionals is important in achieving the onchocerciasis control objectives through mass ivermectin therapy.

METHODS

Eight hundred and ninety subjects from 204 randomly selected households (based on cluster of households) were interviewed using structured questionnaires and in-depth interviews. Responses concerning the adverse effects of ivermectin at the first and sixth rounds were obtained using self-report and treatment records.

RESULTS

Of the 890 individuals, 40.67% presented with adverse reactions at the first round of treatment (TX(1)). This was reduced to 15.06% at the sixth (TX(6)) round of treatment. Pains in joints were more frequently reported at TX(1) and TX(6), 22.7% and 8.5%, respectively.

CONCLUSION

The relatively mild adverse reaction rates observed at TX(1) did not affect future participation in community treatment with ivermectin, due to adequate community mobilization with health education messages. The current CDTI program has a good chance of achieving the onchocerciasis control program's objectives in Shao, Kwara State, Nigeria.

Outcome of two patient education methods on recruitment and compliance with ivermectin in the treatment of onchocerciasis

Two patient education methods, Information Media (IM) and Social Network (SN), were compared to determine their relative effectiveness on recruitment and subsequent compliance behavior of people infected with onchocerciasis in respect of appointment keeping and ivermectin consumption in existing primary health care facilities in six communities in southwestern Nigeria. Two communities each were randomly assigned to the IM intervention group, two of the SN group, and two served as controls. A total of 1265 persons out of an estimated target population of 5033 infected individuals were enrolled in the study. Coverage rates were higher in the intervention communities (30.3% for SN and 29.9% for IM) than control (7.3%), but the differences between intervention groups was not significant. A drop-off was seen in attendance at the second round of ivermectin distribution. Nearly equal proportions of the intervention groups returned (43.3% for SN and 47.4% for IM), while few control patients came back for their second dose (12.3%). Factors responsible for the low turnout were thought to include the content of educational messages, mobility of community members and limited time available to collect the drugs. Cost considerations led to recommendations to maintain facility based distribution and the SN approach, with greater emphasis on mobilization to increase coverage and compliance.