Burden of disease in Gabon caused by loiasis: a cross-sectional survey

Veletzky, Luzia; Hergeth, Jennifer; Stelzl, Daniel Robert; Mischlinger, Johannes; Manego, Rella Zoleko; Mombo-Ngoma, Ghyslain; McCall, Matthew; Adegnika, Ayôla Akim; Agnandji, Selidji Todagbé; Metzger, Wolfram; Matsiegui, Pierre Blaise; Lagler, Heimo; Mordmüller, Benjamin; Budke, Christine M.; Ramharter, Michael

doi:10.1016/s1473-3099(20)30256-5

Cited by 43 publications

(41 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, in microscopy the probability of detection of blood parasite increases, as the parasite quantity increases and the limit of detection in this study was 100 microfilariae per one milliliter blood. That being said, the median L. loa microfilaraemia in our study sample was high both in CAP (3,100]) and in VEN blood (2,875]). Therefore, if the true population medians of CAP and VEN microfilaraemia are truly above the limit of detection in microscopy, then absolute differences in CAP-VEN microfilaraemia might not contribute to a differential odds of microfilaria detection.…”

Section: Discussionmentioning

confidence: 58%

“…While occurrence of L. loa is geographically confined to forested regions of Western and Central Africa M. perstans is also reported from other global regions such as the Americas [1,2]. To date, research on both infections is neglected and only in recent years studies have demonstrated that loiasis is associated with higher population morbidity and mortality [3,4]. Regarding mansonellosis little is known on its impact on population morbidity and mortality, however, this might be explained by the relatively lesser attention that it receives in comparison to other tropical diseases.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Diagnostic performance of capillary and venous blood samples in the detection of Loa loa and Mansonella perstans microfilaraemia using light microscopy

et al. 2021

Self Cite

View full text Add to dashboard Cite

Background Loa loa and Mansonella perstans–the causative agents of loiasis and mansonellosis—are vector-borne filarial parasites co-endemic in sub-Saharan Africa. Diagnosis of both infections is usually established by microscopic analysis of blood samples. It was recently established that the odds for detecting Plasmodium spp. is higher in capillary (CAP) blood than in venous (VEN) blood. In analogy to this finding this analysis evaluates potential differences in microfilaraemia of L. loa and M. perstans in samples of CAP and VEN blood. Methods Recruitment took place between 2015 and 2019 at the CERMEL in Lambaréné, Gabon and its surrounding villages. Persons of all ages presenting to diagnostic services of the research center around noon were invited to participate in the study. A thick smear of each 10 microliters of CAP and VEN blood was prepared and analysed by a minimum of two independent microscopists. Differences of log2-transformed CAP and VEN microfilaraemia were computed and expressed as percentages. Furthermore, odds ratios for paired data were computed to quantify the odds to detect microfilariae in CAP blood versus in VEN blood. Results A total of 713 participants were recruited among whom 52% were below 30 years of age, 27% between 30–59 years of age and 21% above 60 years of age. Male-female ratio was 0.84. Among 152 participants with microscopically-confirmed L. loa infection median (IQR) microfilaraemia was 3,650 (275–11,100) per milliliter blood in CAP blood and 2,775 (200–8,875) in VEN blood (p<0.0001), while among 102 participants with M. perstans this was 100 (0–200) and 100 (0–200), respectively (p = 0.44). Differences in linear models amount up to an average of +34.5% (95% CI: +11.0 to +63.0) higher L. loa microfilaria quantity in CAP blood versus VEN blood and for M. perstans it was on average higher by +24.8% (95% CI: +0.0 to +60.5). Concordantly, the odds for detection of microfilaraemia in CAP samples versus VEN samples was 1.24 (95% CI: 0.65–2.34) and 1.65 (95% CI: 1.0–2.68) for infections with L. loa and M. perstans, respectively. Conclusion This analysis indicates that average levels of microfilaraemia of L. loa are higher in CAP blood samples than in VEN blood samples. This might have implications for treatment algorithms of onchocerciasis and loiasis, in which exact quantification of L. loa microfilaraemia is of importance. Furthermore, the odds for detection of M. perstans microfilariae was higher in CAP than in VEN blood which may pre-dispose CAP blood for detection of M. perstans infection in large epidemiological studies when sampling of large blood quantities is not feasible. No solid evidence for a higher odds of L. loa microfilariae detection in CAP blood was revealed, which might be explained by generally high levels of L. loa microfilaraemia in CAP and VEN blood above the limit of detection of 100 microfilariae/ml. Yet, it cannot be excluded that the study was underpowered to detect a moderate difference.

show abstract

Section: Discussionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Diagnostic performance of capillary and venous blood samples in the detection of Loa loa and Mansonella perstans microfilaraemia using light microscopy

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…And as disease metrics are increasingly being used by research and public health programme funders to guide their financing decisions, a case can be made that mansonellosis research has become trapped in vicious circle of neglect. 1,7 Research into the disease burden of mansonellosis has not been financed exactly because its disease burden is unknown. 1 Figure 1 Integrated life cycle of the three Mansonella spp.…”

Section: Introductionmentioning

confidence: 99%

“…Until very recently there were no disease burden estimates for the filarial disease loiasis, which has a very similar epidemiological and clinical profile to mansonellosis. 6 , 7 Unlike mansonellosis, however, it was included among the diseases listed in the WHO´s Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN) programme. 11 This was largely because individuals heavily infected with loiasis (i.e.…”

Section: Introductionmentioning

confidence: 99%

An Overview of the Management of Mansonellosis

Ta‐Tang

Luz

Crainey

et al. 2021

RRTM

View full text Add to dashboard Cite

Mansonellosis is caused by three filarial parasite species from the genus Mansonella that commonly produce chronic human microfilaraemias: M. ozzardi, M. perstans and M. streptocerca. The disease is widespread in Africa, the Caribbean and South and Central America, and although it is typically asymptomatic it has been associated with mild pathologies including leg-chills, joint-pains, headaches, fevers, and corneal lesions. No robust mansonellosis disease burden estimates have yet been made and the impact the disease has on blood bank stocks and the monitoring of other filarial diseases is not thought to be of sufficient public health importance to justify dedicated disease management interventions. Mansonellosis´s Ceratopogonidae and Simuliidae vectors are not targeted by other control programmes and because of their small size and out-door biting habits are unlikely to be affected by interventions targeting other disease vectors like mosquitoes. The ivermectin and mebendazole-based mass drug administration (iMDA and mMDA) treatment regimens deployed by the WHO´s Elimination of Neglected Tropical Diseases (ESPEN) programme and its forerunners have, however, likely impacted significantly on the mansonellosis disease burden, principally by reducing the transmission of M. streptocerca in Africa. The increasingly popular plan of using iMDA to control malaria could also affect M. ozzardi parasite prevalence and transmission in Latin America in the future. However, a potentially far greater mansonellosis disease burden impact is likely to come from shortcourse curative anti-Wolbachia therapeutics, which are presently being developed for onchocerciasis and lymphatic filariasis treatment. Even if the WHO´s ESPEN programme does not choose to deploy these drugs in MDA interventions, they have the potential to dramatically increase the financial and logistical feasibility of effective mansonellosis management. There is, thus, now a fresh and urgent need to better characterise the disease burden and ecoepidemiology of mansonellosis so that effective management programmes can be designed, advocated for and implemented.

show abstract

“…Two publications present an infection prevalence of more than 50% in their study population. Nguema et al examined the prevalence of soil-transmitted helminths (STH) and schistosomiasis among schoolchildren of the Northern and Eastern Health regions of Gabon [ 21 ] and Veletzky et al found a prevalence of 50.8% of the filarial parasite Loa loa among the 1232 participants from the Gabonese departments of Tsamba-Magotsi and Ogooué et des Lacs [ 22 ]. Studies conducted in our study area have assessed incidences of STH and schistosomiasis ranging from 65% in a study with 388 pregnant women in 2010 [ 23 ] to 23% of schistosomiasis infections in a smaller study with 54 pregnant women in 2019 [ 24 ] and 26% for schistosomiasis as well as 15% for STH in 614 schoolchildren living in Lambaréné in 2020 [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Impact of Helminth Infections during Pregnancy on Vaccine Immunogenicity in Gabonese Infants

et al. 2020

Self Cite

View full text Add to dashboard Cite

Helminth infections are common in sub-Saharan Africa. Besides direct clinical effects, a bias towards a T helper type 2 (Th2) cell immune response is observed. The consequences of parasite infection during pregnancy for the mother and particularly for the fetus and the newborn can be severe and may include impaired immune response during acute infection and vaccination. Here, we present data of immune responses to vaccines given within the expanded program on immunization (EPI) of infants born to helminth infected or non-infected mothers. The study was conducted in Lambaréné and surroundings, Gabon. Maternal helminth infection was diagnosed microscopically using the Kato-Katz method for soil-transmitted helminths (STH), urine filtration for Schistosoma haematobium infections and the saponin-based method for filarial infections. Plasma antibody levels to different vaccine antigens were measured in mothers and their offspring by enzyme-linked immunosorbent assay (ELISA) at different timepoints. We found 42.3% of the mothers to be infected with at least one helminth species. Significantly lower anti-tetanus toxoid immunoglobulin (Ig) G was detected in the cord blood of infants born to helminth infected mothers. Following vaccination, immune responses of the infants to EPI vaccines were similar between the two groups at nine and 12 months. Even though infection with helminths is still common in pregnant women in Gabon, in our setting, there was no evidence seen for a substantial effect on infants’ immune responses to vaccines given as part of the EPI.

show abstract

Burden of disease in Gabon caused by loiasis: a cross-sectional survey

Cited by 43 publications

References 20 publications

Diagnostic performance of capillary and venous blood samples in the detection of Loa loa and Mansonella perstans microfilaraemia using light microscopy

Diagnostic performance of capillary and venous blood samples in the detection of Loa loa and Mansonella perstans microfilaraemia using light microscopy

An Overview of the Management of Mansonellosis

Impact of Helminth Infections during Pregnancy on Vaccine Immunogenicity in Gabonese Infants

Contact Info

Product

Resources

About