Status of parasitological indicators and morbidity burden of onchocerciasis after years of successive implementation of mass distribution of ivermectin in selected communities of Yeki and Asosa districts, Ethiopia

Association of haemato-biochemical indices and blood composite ratios with microfilaridermia in Onchocerciasis patients

BACKGROUND

Onchocerciasis causes chronic systemic inflammation. Several studies have used markers such as haemato-biochemical indices to predict the occurrence of systemic inflammation. This study assessed the variability and predictability of haemato-biochemical indices and blood composite ratios (BCRs) in microfilariae positive (MF+) and microfilariae negative (MF-) subgroups of onchocercomata participants.

METHODS

One hundred and five (105) MF + and 34 MF- participants were retrospectively recruited into the study. Screening for the presence of O. volvulus microfilariae was done from skin snips taken from the left and right iliac crests of participants using established and approved protocols. Haematological and biochemical indices were measured using standard laboratory automated analyzers. Blood composite ratios (BCRs) were calculated as ratios of the absolute parameters involved.

RESULTS

A significantly increased total WBC, absolute eosinophil, eosinophil percent and absolute basophil were observed in the MF + participants compared to MF- participants. Reduced gamma-glutamyl transferase (GGT) with increased estimated glomerular filtration rate (eGFR) was significantly associated with MF + participants compared to MF- participants. BCRs were significantly higher for eosinophil-to-neutrophil ratio (ENR), eosinophil-to-monocyte ratio (EMR), eosinophil-to-basophil ratio (EBR) and eosinophil-to-lymphocyte ratio (ELR) in MF + participants compared to MF- participants. After multivariate adjustment, onchocercomata participants with increased eosinophil counts (aOR = 13.86, 95% CI [2.07-92.90], p = 0.007), ENR x10 (aOR = 1.42, 95% CI [1.05-1.93], p = 0.025), EMR (aOR = 2.64, 95% CI [1.25-5.60], p = 0.011), EBR (aOR = 1.07, 95% CI [1.01-1.10], p = 0.020) and ELR x10 (aOR = 1.69, 95% CI [1.14-2.51], p = 0.009) were more likely to have microfilaridermia.

CONCLUSIONS

Elevated eosinophil counts with higher ENR, EMR, EBR and ELR levels are significantly associated with microfilaridermia in onchocercomata participants. Combining BCRs with eosinophil count significantly led to an improvement in the conventional model for predicting microfilaridermia.

Presumed Onchocerciasis Chorioretinitis Spilling over into North America, Europe and Middle East

BACKGROUND

Newer generation ophthalmologists practicing in the developed world are not very familiar with some tropical ocular diseases due to the absence of reports in the ophthalmic literature over the past thirty years. Because of world globalization or due to influx of immigrants from sub-Saharan Africa, exotic retinal diseases are being encountered more often in ophthalmology clinics.

METHODS

A multicenter case series of chorioretinitis or optic neuritis with obscure etiology that used serial multimodal imaging.

RESULTS

Four cases qualified with the diagnosis of presumed ocular onchocerciasis based on their residence near fast rivers in endemic areas, multimodal imaging, long term follow-up showing progressive disease and negative workup for other diseases. Characteristic findings include peripapillary choroiditis with optic neuritis or atrophy, subretinal tracts of the microfilaria, progressive RPE atrophy around heavily pigmented multifocal chorioretinal lesions of varying shapes, subretinal white or crystalline dots, and response to ivermectin. Typical skin findings are often absent in such patients with chorioretinitis rendering the diagnosis more challenging.

CONCLUSIONS

Familiarity with the myriad ocular findings of onchocerciasis, and a high-degree of suspicion in subjects residing in endemic areas can help in the correct diagnosis and implementation of appropriate therapy. Onchocercal chorioretinitis is a slow, insidious, progressive, and prolonged polymorphous disease.

Burden of neglected tropical diseases and access to medicine and diagnostics in Ethiopia: a scoping review

BACKGROUND

More than 1.7 billion people are affected by neglected tropical diseases (NTDs) worldwide. Forty percent of the NTD-affected people live in Africa with the poorest, most vulnerable, and hard to reach geographical areas. The NTDs cause significant social and economic burden and deepen marginalization and stigmatization. The World Health Organization's current roadmap for NTD aims to prevent, control, eliminate, or eradicate 20 tropical diseases. Ethiopia experiences a high burden of these diseases, but current access to diagnostics, medicine, and/or care has been little explored to inform the country's NTD strategic plan. The overall purpose of the scoping review was to map and characterize the burden of NTDs and challenges in access to diagnostics, medicine, and/or care in Ethiopia.

METHODS

A systematic search of evidence was conducted in PubMed, Cochrane Library, and Google Scholar from January 2000 until May 2022, without restrictions of language or study design. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Review was followed for screening of studies. Key findings were extracted and narrated qualitatively.

RESULTS

The search resulted in 4532 articles, of which 105 met the inclusion criteria and were included in the scoping review under three themes: burden of NTDs, access to diagnostics, medicine and/or care, and key barriers. Although gains have been made in the prevention and control of NTDs in Ethiopia, the burden remains high, and progress in access to diagnostics, medicine/drugs, and/or care is very slow. Poverty, poor quality of life, and underfunding of NTD programs decelerate the process of NTD elimination program in the country.

CONCLUSIONS

The scoping review identified a considerable number of studies on the burden of NTDs in Ethiopia and strategies for diagnosis, treatment, and/or care; however, there is a paucity of evidence on the suitability and potential benefits of novel diagnostic technologies and medicines in the country. A regular review and analysis of such country-level evidence is important to inform the country NTDs roadmap and local implementation strategies.

Impact of ivermectin mass drug administration on burden of soil-transmitted helminths in onchocerciasis control and elimination programs, Yeki district, southwest Ethiopia

Community-directed treatment with ivermectin (CDTi) is the primary strategy employed to control and eliminate human onchocerciasis in Ethiopia. After long-term mass distribution for onchocerciasis, ivermectin is expected to have additional benefits beyond the envisioned targets by reducing the burden of other co-endemic parasitic infections as to STHs. To date, studies focused on the collateral impact of CDTi on STH in Ethiopia are scanty. Two community-based cross-sectional surveys (baseline in 1997 and post-CDTi in 2017) were conducted to evaluate the impact of long-term CDTi employed to control and eliminate onchocerciasis on the burden of STH infections in Yeki district of southwest Ethiopia. Stool samples were collected and examined using Ritchie`s concentration and Kato-Katz techniques in the baseline and current study, respectively. Overall, 188(38.3%, 95% Confidence interval (CI) 34.1–42.7%) individuals were positive at least for any of the STH species from 491 study participants in the post-CDTi. The prevalence of A. lumbricoides, hookworms, and T. trichiura was 11.2% (95% CI 8.7–14.3%), 16.3% (95% CI 13.3–19.8%), and 29.9% (95% CI 26.1–34.1%), respectively. Individuals aged 5–9 years had a significantly higher prevalence of A. lumbricoides (Adjusted odds ratio (AOR) 6.5, 95% CI 1.7–25.4), T. trichuria (AOR 8, 95% CI 2.6–25.1), and any STH infection (AOR 5, 95% CI 1.7–14.7) than those of ≥ 51 years. Also, significantly higher prevalences of T. trichuria infection were observed in individuals aged 10–14 years (AOR 4.1, 95% CI 1.7–9.9), 15–20 years (AOR 3.1, 95% CI 1.2–8.1), 21–30 years (AOR 2.4, 95% CI 1.1–5.5), and 31–40 years (AOR 3.2, 95% CI 1.3–7.5) compared with those of ≥ 51 years. The prevalence of A. lumbricoides was significantly higher in males (AOR 0.5, 95% CI 0.3–0.9). Of the 491 study participants, only data from 400 individuals who had not been involved in a mass drug administration (MDA) with other STH anthelmintics were considered in the comparative analysis. Before CDTi, the prevalence of A. lumbricoides, T. trichiura, hookworm, and any STH infection was 47.1% (95% CI 41.6–52.7%), 3.3% (95% CI 1.8–5.9%), 37.9% (95% CI 32.7–43.5%), and 58.8% (95% CI 53.2–64.1%), respectively. Long-term CDTi considerably reduced the prevalences of A. lumbricoides and hookworm by 76.2% and 56.9%, respectively (p < 0.001). Nonetheless, CDTi did not affect the prevalence of T. trichiura infection and, in contrast, it was significantly higher in the current study (P < 0.001). Overall post-CDTi prevalence of any STH infection was considerably lower than reported in the baseline (p < 0.001). It is evidenced that long-term CDTi for onchocerciasis control and elimination had additional benefits by reducing the prevalence of STH infections specifically of A. lumbricoides and hookworm, but had no impact on infections with T. trichuria. Our finding of additional health benefits of large-scale ivermectin administration taking it will aid to increase positive engagement and sustain participation of communities during MDA campaigns, and strengthen governmental and non-governmental organizations (NGOs) support for the undergoing national onchocerciasis elimination program.