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Lymphatic filariasis and onchocerciasis are parasitic helminth diseases that constitute a serious public health issue in tropical regions. The filarial nematodes that cause these diseases are transmitted by blood-feeding insects and produce chronic and long-term infection through suppression of host immunity. Disease pathogenesis is linked to host inflammation invoked by the death of the parasite, causing hydrocoele, lymphoedema, and elephantiasis in lymphatic filariasis, and skin disease and blindness in onchocerciasis. Most filarial species that infect people co-exist in mutualistic symbiosis with Wolbachia bacteria, which are essential for growth, development, and survival of their nematode hosts. These endosymbionts contribute to inflammatory disease pathogenesis and are a target for doxycycline therapy, which delivers macrofilaricidal activity, improves pathological outcomes, and is effective as monotherapy. Drugs to treat filariasis include diethylcarbamazine, ivermectin, and albendazole, which are used mostly in combination to reduce microfilariae in blood (lymphatic filariasis) and skin (onchocerciasis). Global programmes for control and elimination have been developed to provide sustained delivery of drugs to affected communities to interrupt transmission of disease and ultimately eliminate this burden on public health.

[...]intervention programmes targeting elimination of onchocerciasis as a public health problem do not take into account OAE. [...]OAE may increase onchocerciasis-related mortality among children and adolescents. [...]NS incidence in Uganda has been brought down to zero [4]. The household clustering of PWE has led communities and local healthcare workers to wrongly believe that epilepsy is contagious and transmissible by direct contact, hence increasing stigma. [...]educating communities and health professionals about OAE will reduce stigma and motivate people to take ivermectin [23].

At the Pasteur Institute of Montevideo, María Eugenia Francia tackles a cause of vision problems in babies. At the Pasteur Institute of Montevideo, María Eugenia Francia tackles a cause of vision problems in babies.

Objective Sierra Leone, a country where onchocerciasis is endemic in 14 of the 16 districts, was the focus of our investigation. Despite 17 rounds of annual ivermectin treatment since 2005, a report circulated by a local politician indicated an increase in cases of suspected onchocerciasis-related vision impairment in two villages (Mangobo and Petifu) in Tonkolili district. In response, the National Neglected Tropical Disease Program conducted a comprehensive investigation. Ophthalmological, parasitological, and serological tests were conducted using standard procedures to determine the relationship between self-reported vision loss and onchocerciasis in adults. In addition, serological tests were carried out on children aged 5 to 9 years to assess the recent status of exposure to onchocerciasis in the two villages. Results Reported vision loss in 37 patients was mainly due to cataracts (35.1%), allergic conjunctivitis (18.9%), refractive error (10.8%), and other conditions not related to onchocerciasis. There were 40.7% of all adults ( N  = 54) tested and 29.0% of 31 persons with self-reported vision loss who were positive for Ov-16 IgG4 antibodies, suggesting a history of exposure to onchocerciasis. However, otoscopic eye examinations and microscopic skin snip tests were all negative for Onchocerca volvulus microfilariae, indicating no active or low-intensity infection among adults and a low or zero risk of serious ocular morbidity in the two villages. Onchocerciasis may no longer be a major cause of blindness in these two villages. Apparently, 4.6% of 153 children aged 5 to 9 years tested positive for Ov-16 IgG4 antibodies, suggesting that onchocerciasis transmission is likely still ongoing in the two villages. The data presented here suggest that more annual rounds of mass treatment with ivermectin with high coverage are needed to eliminate onchocerciasis transmission in this area.

BACKGROUND: The African Programme for Onchocerciasis Control (APOC) has refocused its goals on the elimination of infection where possible, seemingly achievable by 15–17 years of annual mass distribution of ivermectin in some African foci. Previously, APOC had focused on the elimination of onchocerciasis as a public health problem. Timeframes have been set by the World Health Organization, the London Declaration on Neglected Tropical Diseases and the World Bank to achieve these goals by 2020–2025. METHODS: A novel mathematical model of the dynamics of onchocercal disease is presented which links documented associations between Onchocerca volvulus infection and the prevalence and incidence of morbidity and mortality to model outputs from our host age- and sex-structured onchocerciasis transmission framework (EpiOncho). The model is calibrated for African savannah settings, and used to assess the impact of long-term annual mass administration of ivermectin on infection and ocular and skin disease and to explore how this depends on epidemiological and programmatic variables. RESULTS: Current onchocerciasis disease projections, which do not account for excess mortality of sighted individuals with heavy microfilarial loads, underestimate disease burden. Long-term annual ivermectin treatment is highly effective at reducing both the morbidity and mortality associated with onchocerciasis, and this result is not greatly influenced by treatment coverage and compliance. By contrast, impact on microfilarial prevalence and intensity is highly dependent on baseline endemicity, treatment coverage and systematic non-compliance. CONCLUSIONS: The goals of eliminating morbidity and infection with ivermectin alone are distinctly influenced by epidemiological and programmatic factors. Whilst the former goal is most certainly achievable, reaching the latter will strongly depend on initial endemicity (the higher the endemicity, the greater the magnitude of inter-treatment transmission), advising caution when generalising the applicability of successful elimination outcomes to other areas. The proportion of systematic non-compliers will become far more influential in terms of overall success in achieving elimination goals.

Intra-orbital hydatid cyst is a very rare pathological entity that affects children and the young adults; it is secondary to the development in the orbit of the echinococcus granulosis tapeworm. Its frequency does not exceed 1% of all cases of hydatid disease. Clinical presentation of intra-orbital hydatid cyst is dominated by proptosis and a decrease in visual acuity, complete surgical excision is difficult, evolution is generally better when the treatment is early before the installation of irreversible optic atrophy. We report one case of a 3 years old girl operated for right intra-orbital hydatid cyst who presented with proptosis and blindness. Complete removal was difficult and puncture of the cyst was performed followed by excision of its membrane with good post-operative results. We also discuss the different epidemiological, clinical, radiological and therapeutic aspects of intra-orbital hydatid cyst and a review of literature of this rare pathology.

A healthy 25-year-old male pork handler presented to a clinic in India with painless vision loss for 6 months in his left eye. Visual acuity was 20/20 in the right eye and light perception in the left.

Owing to the defective pupil response to light, the visual loss was attributed to occipital and chiasmal/prechiasmal lesions. Radioimaging is the gold standard for diagnosis of NCC, and stages have been described depending on parenchymal reaction in the brain and calcification changes in the cyst itself.1 On imaging, the presence of a ‘hole with a dot’ appearance due to the scolex is characteristic in early stages. The parasite can also invade the ocular and orbital tissue with/without NCC, and become the cause of visual loss.2 Such cases require delicate ocular surgery for removal of the cyst while maintaining the ocular anatomy, whereas management of NCC is predominantly with cysticidal medical therapy. Treatment delay may be detrimental to visual recovery in cases of visual loss due to NCC.

Background. Infection with Onchocerca volvulus is associated with the prevalence of severe visual impairment and blindness. However, longitudinal studies of the incidence of blindness caused by onchocerciasis are scarce. Methods. The relationship, at the individual level, between infection with O. volvulus microfilariae and bilateral blindness was examined, by use of data collected, during the Onchocerciasis Control Programme in western Africa (OCP), from 2315 villages in 11 countries. The data were analyzed by Poisson maximum-likelihood techniques with adjustment for overdispersion. Results. A total of 297,756 persons were eligible for follow-up in the cohort, and, during 1971–2001, these persons accumulated 367,788 person-years of follow-up without blindness. A total of 673 bilateral cases of blindness occurred during this period; 29.7% were caused by onchocerciasis. After ivermectin therapy was introduced (during 1988–2001), only 19.6% of cases were caused by onchocerciasis. The incidence of blindness was significantly and positively associated with increasing microfilarial burden ( P < .001 ). Overall, female subjects had an ∼40% lower risk of becoming blind than did male subjects ( P < .001 ). After an initially high incidence of blindness at the beginning of the OCP, the rate of blindness from causes other than onchocerciasis remained approximately constant during follow-up. Conclusions. We demonstrate, in a comprehensive data set and in both sexes, a direct relationship between microfilarial load and the incidence of blindness.