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[
J Neurogenet
]
John Sulston changed the way we do science, not once, but three times - initially with the complete cell lineage of the nematode <i>Caenorhabditis elegans</i>, next with completion of the genome sequences of the worm and human genomes and finally with his strong and active advocacy for open data sharing. His contributions were widely recognized and in 2002 he received the Nobel Prize in Physiology and Medicine.
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[
Pathogens,
2020]
We investigated urinary N-acetyltyramine-O,-glucuronide (NATOG) levels as a biomarker for active <i>Onchocerca volvulus</i> infection in an onchocerciasis-endemic area in the Democratic Republic of Congo with a high epilepsy prevalence. Urinary NATOG was measured in non-epileptic men with and without <i>O. volvulus</i> infection, and in <i>O. volvulus-</i>infected persons with epilepsy (PWE). Urinary NATOG concentration was positively associated with microfilarial density (<i>p</i> < 0.001). The median urinary NATOG concentration was higher in PWE (3.67 M) compared to men without epilepsy (1.74 M), <i>p</i> = 0.017; and was higher in persons with severe (7.62 M) compared to mild epilepsy (2.16 M); <i>p</i> = 0.008. Non-epileptic participants with and without <i>O. volvulus</i> infection had similar NATOG levels (2.23 M and 0.71 M, <i>p</i> = 0.426). In a receiver operating characteristic curve analysis to investigate the diagnostic value of urinary NATOG, the area under the curve was 0.721 (95% CI: 0.633-0.797). Using the previously proposed cut-off value of 13 M to distinguish between an active <i>O. volvulus</i> infection and an uninfected state, the sensitivity was 15.9% and the specificity 95.9%. In conclusion, an <i>O. volvulus</i> infection is associated with an increased urinary NATOG concentration, which correlates with the individual parasitic load. However, the NATOG concentration has a low discriminating power to differentiate between infected and uninfected individuals.
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Raimon S, Yibi Logora M, Kumar-Singh S, Suliman A, Abd-Elfarag G, Y Carter J, Nelson Siewe Fodjo J, Colebunders R, Hotterbeekx A, Sebit W, De Witte P
[
Int J Infect Dis,
2019]
OBJECTIVES: Epidemiological evidence links onchocerciasis with the development of epilepsy. We aimed to detectOnchocerca volvulus microfilariae or its bacterial endosymbiont, Wolbachia, in the cerebrospinal fluid (CSF) of persons with onchocerciasis-associated epilepsy (OAE). METHODS: Thirteen persons with OAE andO. volvulus skin snip densities of >80 microfilatiae were recruited in Maridi County (South Sudan), and their CSF obtained. Cytospin centrifuged preparations of CSF were examined by light microscopy for presence of O. volvulus microfilariae. DNA was extracted from CSF to detect O. volvulus (O-150 repeat) by quantitative real-time PCR, and Wolbachia (FtsZ gene) by standard PCR. To further investigate if CSF from onchocerciasis-infected participants could induce seizures, 3- and 7-days old zebrafish larvae were injected with the CSF intracardially and intraperitoneally, respectively. For other zebrafish larvae, CSF was added directly to the larval medium. RESULTS: No microfilariae, parasite orWolbachia DNA were detected in any of the CSF samples by light microscopy or PCR, respectively. All zebrafish survived the procedures and none developed seizures. CONCLUSION: The absence of O. volvulus in CSF suggests that OAE is likely not caused by direct parasite invasion into the central nervous system, but by another phenomenon triggered by O. volvulus infection.
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[
Indian J Med Res,
1982]
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[
Infection,
1977]
Serum samples from persons who lived in areas where onchocerciasis occurred or who had filariasis were examined with the complement fixation test and the indirect hemagglutination test for the presence of antibodies against crude extracts from Dirofilaria immitis, Onchocerca volvulus, Dipetalonema viteae, and Ascaris suum. The results could be interpreted as follows: 1. The indirect hemagglutination test was more sensitive than the complement fixation test for the demonstration of antibodies in sera from European and indigenous inhabitants of endemic areas. 2. There were no differences between the responses to the four crude worm extracts among the groups of 21 patients with Loa loa, 12 patients with Onchocerca volvulus, 11 patients with Dipetalonema perstans, and 22 patients with clinical filariasis in whom no microfilaria had been found. It was concluded that the examination with crude extracts cannot give any information about the antigens that had caused the stimulation of antibodies.
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[
Tropenmed Parasitol,
1980]
464 persons of whom 189 proved to be infected with microfilariae of Wuchereria bancrofti and/or Onchocerca volvulus were examined for adverse reactions due to diethylcarbamazine, which was administered during a filariasis control campaign. Persons older than 20 years of age were significantly more affected than younger persons and men showed distinctly more side effects than women. The most frequent complaints were skin reactions followed by gastrointestinal complications. The significantly highest rate of adverse reactions was observed in persons being infected with microfilariae of O. volvulus, whereas no significant difference was registered between side effect rates of bancroftian microfilaria carriers and non-infected persons. It is concluded that in areas where both filarial species are endemic, infections with O. volvulus are a limiting factor for the control of bancroftian filariasis by means of mass treatment with diethylcarbamazine.
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[
East Afr Med J,
1995]
Onchocerciasis affects 7% of Uganda's population and 1.5 million more people are at risk of infection with Onchocerca volvulus, the nematode that causes the disease. This paper reports the results of part of a multi-centre study whose objective was to determine the prevalence of onchocercal skin disease and its associated psychosocial importance in Uganda. The study employed a standardised clinical dermatological survey method along with the use of structured questionnaires, focus group discussions and key informant interviews. Out of a total of 993 persons examined to determine the prevalence of onchocercal skin lesions 253 persons were interviewed to determine the psychosocial importance of the disease. The results indicate that onchocercal skin disease is associated with a variety of psychosocial, physical and economic effects. The disease also leads to stigmatisation of affected persons and their families. It is suggested that dermatological effects of onchocerciasis should be recognised as an important cause of morbidity in Uganda.
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[
Am J Trop Med Hyg,
2000]
The mechanism by which the minority of patients with onchocerciasis exhibiting the hyperreactive (sowda) form of the disease may be able to kill the microfilariae of Onchocerca volvulus is still poorly understood. In this study, the relative amounts of arachidonate and linoleate in serum phospholipids and triglycerides were investigated by gas chromatography both in patients infected with O. volvulus who exhibited either a hyperreactive or a generalized form of onchocerciasis and in persons with no filarial infections. Remarkable differences were observed in the serum triglycerides but not in the phospholipids. In comparison to persons without any filarial infection, significantly lower relative amounts of arachidonate--indicated by elevated triene-tetraene ratios--and of linoleate--indicated by lower diene + tetraene - triene values--were detected in patients with hyperreactive onchocerciasis, and less pronounced differences were found in persons with generalized onchocerciasis. The relationship between reduced amounts of arachidonate and linoleate in serum triglycerides and possible implications on the eicosanoid production in the host-parasite relationship leading to parasite elimination are discussed.
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[
Comput Methods Programs Biomed,
1990]
ONCHOSIM is a computer program for modelling the transmission and control of the tropical parasitic disease onchocerciasis, or river blindness. It is developed in collaboration with the Onchocerciasis Control Programme in West Africa (OCP), and is used as a tool in the evaluation and planning of control operations. The model comprises a detailed description of the life history of the parasite Onchocerca volvulus and of its transmission from person to person by Simulium flies. The effects of different control strategies, based on larvicide application and chemotherapy (ivermectin), on the transmission and on the disease symptoms can be evaluated and predicted. In the program two simulation techniques are mixed. Stochastic microsimulation is used to calculate the life events of individual persons and inhabitant parasites, while the dynamics of the Simulium population and the development of the parasite in the flies are simulated deterministically. Output of ONCHOSIM conforms to the format in which data collected by the OCP are reported. This enables detailed checking of model specifications against empirical data. Output can also consist of summarizing key indices for the intensity of onchocerciasis infection, which is especially useful for comparing the effectivity of control strategies.
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[
Am J Trop Med Hyg,
1980]
The indirect hemagglutination (IHA) test done with turkey red cells was applied to 173 serum samples obtained from patients and persons exposed to Wuchereria bancrofti and Brugia malayi in endemic areas of Peninsular Malaysia. A crude extract of adult worms of the rat filaria, Breinlia booliati, was used as the antigen. When a titer of 1:16 was taken as negative, positive IHA test rates in sera from microfilaria-negative persons in endemic areas, microfilaremic cases, and patients with clinical filariasis were 13%, 75%, and 80%, respectively. Results of the IHA test correlated well with results obtained with the indirect fluorescent technique.