Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033774 (pruritus)
 14,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The greatest burdens related to human onchocerciasis are the result of the eye and skin lesions and severe itching produced by the microfilariae. Although the major manifestations of the disease do show geographical variation (e.g. onchocercal blindness is not a common complication in all endemic countries), they are often sufficiently severe to prevent human use of the often very fertile land close to the rivers in which the vectors breed. Though for many years thought to be of relatively minor importance compared with onchocercal eye disease, the skin lesions of onchocerciasis have recently been shown to be a major socio-economic burden, in terms of disability-adjusted life-years. The demonstration of an excellent correlation between the prevalence of palpable nodules in a community and the community microfilarial load has led to the development of rapid, safe and non-invasive methods to assess and map the levels of endemicity across whole countries. This has enabled mass treatment with Mectizan (ivermectin, MSD) to be targeted first at hyperendemic communities. Estimates of the burden of onchocerciasis will continue to change as better means of measurement become available. It seems possible, however, that use of Mectizan will eliminate the disease before its true burden can be estimated accurately.
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PMID:Onchocerciasis: the burden of disease. 986 Dec 75

Onchocerciasis has been reported in Sudan since 1908 and now prevails in three endemic regions known as the southern, northern and eastern foci. The southern focus is the largest, with nodule and blindness rates exceeding 80% and 12%, respectively, in certain villages. Onchocercal infection in this region causes only a mild skin reaction although microfilarial loads in the skin are high. In contrast, those with onchocerciasis in the northern focus, located between the fourth and fifth Nile cataracts, present with limited but severe skin reactions, low nodule rates (16%), low microfilarial loads in the skin and no ocular involvement. The characteristics of patients from the eastern focus, close to the border with Ethiopian border are similar to those in the north, although most onchocercal skin disease in this area comprises the severe localized pruritus known as sowda.
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PMID:The burden of Onchocerca volvulus in Sudan. 986 Dec 78

A multi-centre, double-blind, placebo-controlled trial of the effect of Mectizan (ivermectin, MSD) treatment on the skin disease and severe itching associated with onchocerciasis was carried out in the forest zones of Nigeria, Ghana and Uganda. Overall, 4072 subjects, none of whom had received Mectizan previously, were enrolled and allocated into four groups, to receive Mectizan every 3, 6 or 12 months or placebo every 3 months. Subjects with skin lesions were stratified within each treatment group to ensure equal representation. Each subject was given a clinical examination and interviewed on enrolment and then 3-monthly for 15 months. The presence and severity of itching were determined by open-ended questions followed by probing questions. Skin lesions were classified and their severity graded using a standard system. Analysis of the results was restricted to the data from the 1530 subjects who received all their scheduled treatments and attended all the follow-up visits. From 6 months onwards, all subjects who had received Mectizan reported less severe itching, had lower prevalences of reactive skin lesions and had less severe skin lesions than those in the placebo group (P < 0.05 for each). The greatest reductions, in both itching and skin disease, were seen in subjects treated with Mectizan every 6 months. Mectizan treatment is therefore beneficial for the control of troublesome itching and for reducing the prevalence and severity of skin disease causes by Onchocerca. it is recommended that mass distribution of Mectizan to communities in the study areas be carried out at 6-monthly intervals for maximum efficacy.
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PMID:A multi-centre study of the effect of Mectizan treatment on onchocercal skin disease: clinical findings. 986 Dec 80

In Sierra Leone, a double-blind placebo-controlled trial of 5, 6-monthly doses of ivermectin was conducted in 6 communities with hyperendemic onchocerciasis to determine compliance rates of ivermectin. The researchers had earlier found a significantly higher compliance rate with ivermectin than placebo (64% vs. 57% at 3rd treatment round). They then analyzed data from the 589 persons receiving ivermectin to identify determinants of increased and decreased subsequent compliance to ivermectin treatment. They also administered a questionnaire in a double-blind fashion to 1847 people attending the 4th treatment round in communities mesoendemic for onchocerciasis in Kaduna State in Nigeria. They aimed to focus on subjective responses to ivermectin treatment (e.g., itching). In Sierra Leone, the multiple logistic regression analysis revealed significant associations between complete compliance with ivermectin and leopard skin depigmentation (odds ratio [OR] = 1.56; p = 0.04), the severity of side effects of treatment (OR = 1.68, p = 0.001), fulfilling the exclusion criteria for treatment (OR = 2.26; p = 0.01), and long-term residence in the community (12 years) (OR = 0.54; p = 0.003). In Nigeria, none of the subjective responses to ivermectin treatment (which revolved around eye pain, body pains, itching, dizziness, chronic bad vision, and severity) clearly improved after 3 years of treatment. The ivermectin group tended to have the same non-specific positive comments about treatment (e.g., made healthy) as the placebo group. Negative comments, which usually related to adverse reactions, were more common in the ivermectin group. Ivermectin did not have consistent effects on visual acuity, height, weight, or hematocrit when compared with the placebo. The findings from Sierra Leone but not those in Nigeria can be used to develop health promotion messages. Those from Nigeria suggest that it would be difficult to maintain the high compliance rates needed for long periods if mass dosing programs are to have a long-term impact on onchocerciasis.
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PMID:Maintaining compliance to ivermectin in communities in two West African countries. 1016 Mar 75

400 people in Gilgel Ghibe, southwestern Ethiopia, were subjected to parasitological and clinical examination to determine the prevalence and intensity of onchocerciasis. Its association with entomological transmission indices such as the parous rate and annual transmission potential (ATP) were determined simultaneously. Two skin snips per person were taken and examined for microfilariae of Onchocerca volvulus. In addition, collections of adult blackfly were done from human baits seated in pairs at 4 representative sites at the riverbank and away from the riverbank. Flies were then dissected for parity and infections with O. volvulus. Among the 228 people examined, the prevalence of the disease was low (17%), being higher in males than in females (19% vs. 14%). The geometric mean of microfilarial density was 11.1 mf per skin snip. Itching and skin changes were the most common signs and symptoms of the disease. The predominant anthropophilic blackfly species was Simulium (Edwardsellum) damnosum s.l. The annual parous rate was 74.7%, while ATP was 1669.5, being higher at the riverbank than at farther sites, suggesting a greater risk of infection by the riverside. In conclusion, the low prevalence of onchocerciasis vis-a-vis the high ATP level could be caused by the possible presence of bovine onchocerciasis in the area. Further studies employing molecular techniques are needed to identify O. volvulus from other filariae in flies.
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PMID:Onchocerciasis in Gilgel Ghibe River Valley southwest Ethiopia. 1077 86

Treatment of onchocerciasis with diethylcarbamazine (DEC) or ivermectin is associated with a posttreatment reaction characterized by fever, tachycardia, hypotension, lymphadenopathy, and pruritus. To investigate the role of the Wolbachia bacterial endosymbiont of Onchocerca volvulus in these reactions, serum samples collected before and after treatment with either anthelmintic were assessed for evidence of Wolbachia DNA. By use of real-time quantitative polymerase chain reaction, Wolbachia DNA was detected in both groups-with significantly higher levels in those who received DEC (P <.0001). In the ivermectin group, there was a significant correlation between levels of bacterial DNA and serum tumor necrosis factor-alpha (P =.013). Peak DNA levels correlated with reaction scores (P =.048). Significant correlations were also seen between Wolbachia DNA and the antibacterial peptides calprotectin (P =.021) and calgranulin B (P <.0001). These findings support a role for Wolbachia products in mediating the inflammatory responses seen following treatment of onchocerciasis and suggest new targets for modulating these reactions.
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PMID:Bacterial endosymbionts of Onchocerca volvulus in the pathogenesis of posttreatment reactions. 1192 Feb 98

A cross-sectional survey was undertaken to determine the magnitude, manifestations, and practices related to Onchocerciasis on 1337 students of six junior secondary schools of Kafa Zone in January 1993. Information on symptoms of the disease and the frequency of common practices that would bring the subjects to the breeding sites was collected by interview, while physical measurements and clinical examination was used to collect data on visual acuity, nutritional status and objective manifestations of the disease. Skin snip from both gluteal areas was examined to determine the microfilarial rate and density of infection, while nutritional status using Body Mass Index for Age (BMI-for Age), and visual impairment following the standard procedures was categorized. The majority, 1179 (88.2%) of the subjects, were aged 15 years and less of which males constituted 54.5% (728). The overall microfilarial carrier rate was 15.6% (95% CI = 13.7-17.6%) while the density of infection was 1.4 mf/mg skin snip. The prevalence and density of infection varied significantly among the twelve aggregates of villages identified based on the similarity of the ecological feature and contiguity of home address of the students. Males had significantly higher rate and density of infection but the difference by age was not significant. The prevalence of infection was significantly higher among the students who had reported frequent bathing, swimming, fishing and collecting firewood at/or near the rivers identified as the probable breeding sites of the vector, while there was no statistically significant association between infection and washing clothes, fetching water or crossing over the rivers. Groin lymph nodes enlargement, photophobia and itching were the leading symptoms complained by the infected subjects. However, only itching and the objective features related to the cutaneous Onchocerciasis were significantly associated to the infection. Visual acuity didn't differ among positive and negative subjects. Nutritional status was significantly associated with Onchocercal infection. Based on these findings recommendations are given on the areas of intervention and further study.
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PMID:Onchocerciasis among school children in Kafa, South West Ethiopia. 1196 73

An attempt was made to assess the true public-health importance of onchocercal skin disease throughout the African region and hence provide an objective basis for the rational planning of onchocerciasis control in the area. The seven collaborative centres that participated in the study (three in Nigeria and one each in Ghana, Cameroon, Tanzania and Uganda) were all in areas of rainforest or savannah-forest mosaic where onchocercal blindness is not common. A cross-sectional dermatological survey was undertaken at each site following a standard protocol. At each site, the aim was to examine at least 750 individuals aged 5 years and living in highly endemic communities and 220-250 individuals aged 5 years and living in a hypo-endemic (control) community. Overall, there were 5459 and 1451 subjects from hyper-and hypo-endemic communities, respectively. In the highly endemic communities, the prevalence of itching increased with age until 20 years and then plateaued, affecting 42% of the population aged 20 years. There was a strong correlation between the prevalence of itching and the level of endemicity (as measured by the prevalence of nodules; r=0.75; P<0.001). The results of a multivariate logistic regression analysis showed that, at the individual level, the presence of onchocercal reactive skin lesions (acute papular onchodermatitis, chronic papular onchodermatitis and/or lichenified onchodermatitis) was the most important risk factor for pruritus, with an odds ratio (OR) of 18.3 and 95% confidence interval (CI) of 15.19-22.04, followed by the presence of palpable onchocercal nodules (OR=4.63; CI=4.05-5.29). In contrast, non-onchocercal skin disease contributed very little to pruritus in the study communities (OR=1.29; CI=1.1-1.51). Onchocercal skin lesions affected 28% of the population in the endemic villages. The commonest type was chronic papular onchodermatitis (13%), followed by depigmentation (10%) and acute papular onchodermatitis (7%). The highest correlation with endemicity was seen for the prevalence of any onchocercal skin lesion and/or pruritus combined (r=0.8; P<0.001). Cutaneous onchocerciasis was found to be a common problem in many endemic areas in Africa which do not have high levels of onchocercal blindness. These findings, together with recent observations that onchocercal skin disease can have major, adverse, psycho-social and socio-economic effects, justify the inclusion of regions with onchocercal skin disease in control programmes based on ivermectin distribution. On the basis of these findings, the World Health Organization launched a control programme for onchocerciasis, the African Programme for Onchocerciasis Control (APOC), that covers 17 endemic countries in Africa.
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PMID:Onchocerciasis: the clinical and epidemiological burden of skin disease in Africa. 1206 75

To assess the impact of 5 years of annual community treatment with ivermectin (Mectizan) on the prevalence of onchocerciasis and onchocerciasis-associated morbidity, data collected, before and after such treatment, in the village of Gami, in a hyper-endemic area of the Central African Republic, were analysed. Skin snips from all the villagers treated in 1990 and/or 1995 were used to assess the prevalence and intensity of infection with Onchocerca volvulus. Ocular and dermatological morbidity was assessed by ophthalmological and clinical examinations of the same subjects. Following the five annual treatments, there was a reduction in the prevalence of infection and a dramatic decrease in the microfilarial load of the community. The prevalences of pruritus, onchocercal nodules and impaired vision were all significantly reduced. The results emphasise the long-term benefits of the mass-treatment programmes, particularly for children aged <10 years.
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PMID:The effect of 5 years of annual treatment with ivermectin (Mectizan) on the prevalence and morbidity of onchocerciasis in the village of Gami in the Central African Republic. 1206 76

Onchocerciasis represents a serious public health problem in tropical Africa and parts of Central and South America and Yemen. The adult female parasite lives an average of 10-11 years in the human host, producing millions of microfilariae that invade the tissues of the skin and eye. There is a strong association between the parasite load and the severity of the clinical manifestations of the disease. Of the approximately 17.5 million Africans affected by the disease, 15 million live in the 19 countries participating in the African Program for Onchocerciasis Control (APOC). In the APOC countries, up to 600,000 people are blind or have severe visual impairment and 80% of the total population suffers from onchocercal skin disease and itching. The remaining victims live in the 11 countries of the Onchocerciasis Control Program in West Africa (OCP), where the parasite is on the brink of being eliminated--a factor that has benefited socioeconomic development. The OCP combined vector control with use of the microfilaricide ivermectin. APOC has set the goal of establishing within the next 12 years effective, sustainable, community-based ivermectin treatment programs as well as environmentally safe vector control. An overall coverage rate of 70% of the target population is required for eventual elimination of the disease. Since ivermectin does not interrupt transmission of infection, the regimen must be continued for at least 20 years to ensure long-term control. The rapid epidemiological mapping method has been used to delineate the endemicity levels in most APOC countries.
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PMID:Onchocerciasis control: the APOC strategy. 1229 98


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