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Biomedical subjects

B Thylefors

Publications and source records attributed to B Thylefors.

At least 55 records · Page 3Linked to original sources
PubMed1986

The effect of 7-8 years of vector control on the evolution of ocular onchocerciasis in West African savanna.

The evolution of ocular onchocerciasis was studied in a cohort of 1170 persons over 5 years of age who were examined before the start of and after 7-8 years of effective vector control in 12 originally hyperendemic villages in the central part of the OCP area. The proportion of the cohort which at the outset of vector control was free from ocular onchocerciasis or had an early or recent infection in the form of punctate keratitis only, remained largely free of or lost their signs of ocular infection respectively and only a very insignificant proportion acquired microfilariae in the eyes or developed a severe onchocercal eye lesion at the initial stage. The proportion of the cohort with a heavy ocular microfilarial load had a reduced risk of developing severe eye lesions and no risk of going blind. The proportion of the cohort with already existing severe eye lesions at the advanced stage remained largely unchanged and some lesions at the initial stage disappeared. Blindness occurred only in those who had severe eye lesions at the outset and was comparatively less than in areas of on-going transmission.

Adolescent↗
PubMed1984

The evolution of ocular onchocerciasis in the Volta River Basin Area over a period of five years of vector control.

The results of an ophthalmological evaluation conducted in seven West African savannah villages before and after 5 years of vector control, were analysed to determine the effect of an interrupted or greatly reduced transmission of Onchocerca volvulus on the evolution of ocular onchocerciasis. Cross-sectional data showed a significant reduction of the prevalence of ocular onchocerciasis in five of the villages, and the rates of irreversible ocular lesions and blindness were generally lower after 5 years of vector control. A longitudinal study of a defined population showed that the ocular status of most patients with ocular onchocerciasis remained stable or improved over the 5 year period, particularly in lightly infected cases. The evolution of ocular onchocerciasis showed a deterioration in a minor proportion, restricted to cases of already existing severe lesions, resulting in blindness. A comparison of ophthalmic data from adjacent areas without vector control, indicates that a five year period of vector control may reduce the risk of developing eye lesions or blindness due to onchocerciasis by 50%.

Adolescent↗
PubMed1983

World Health Organization's programme on the prevention of blindness.

The WHO Programme for the Prevention of Blindness was established in 1978, reflecting the need for action against the burden of avoidable blindness, which constitutes an increasingly serious socioeconomic problem in many countries. A vast majority of the world's blind live in developing countries, where unoperated cataract, trachoma, xerophthalmia and onchocerciasis are the main causes of visual loss. Thus, more than two-thirds of blindness encountered in such areas is either preventable or curable. The objectives of the WHO Programme for the Prevention of Blindness are to reduce the amount of avoidable blindness in developing countries, and to make essential eye care available to all. In order to achieve this, blindness prevention must form part of primary health care, which is the basic strategy of the World Health Organization to attain the overall goal of "Health for All by the Year 2000". Emphasis is placed on the establishment of national programmes for the prevention of blindness, geared to local needs and resources. This implies a need for a careful programming process, in relation to the general provision of health services.

Adult↗
PubMed1980

A three-year follow-up of ocular onchocerciasis in an area of vector control.

An evaluation of the effects on onchocerciasis of a 3-year period of vector control was undertaken during 1978 in the Onchocerciasis Control Programme area in West Africa. The results revealed that the overall prevalence of ocular onchocerciasis showed only a slight decrease at the follow-up in 1978, but that there was significantly less infection among children in the age group 5-14 years as compared with 1975. There was a total incidence of ocular signs of onchocerciasis of 8.6% over the 3 years, but also a disappearance of those signs in 11.7% of the sample examined. The incidence of severe onchocercal eye manifestations was low, compared with similar areas of uncontrolled transmission. The particularly low incidence of sclerosing keratitis may be associated with the finding of a significantly decreased microfilarial load in the cornea, whereas the number of living microfilariae in the anterior chamber of the eye was apparently unchanged. The incidence of blindness due to onchocerciasis was low and confined to individuals who already presented severe eye manifestations of the disease before the beginning of the vector control campaign.

Adolescent↗
PubMed1979

Epidemiological aspects of intraocular pressure in an onchocerciasis endemic area.

A field investigation of intraocular pressure in populations in onchocerciasis endemic areas of West Africa revealed a normal pressure distribution in individuals without signs of ocular onchocerciasis or with only microfilariae or reversible lesions in the eye. Females showed a significantly higher mean ocular tension, and in both sexes tension decreased with age. Patients with irreversible onchocercal ocular lesions and signs of anterior uveitis showed a significantly lower and abnormally distributed intraocular pressure. The prevalence of glaucoma was significantly higher in this group, thus indicating that a high intensity of onchocercal infection may be associated with a risk of secondary glaucoma. The presence of microfilariae in the ocular tissues and consequent inflammatory reactions may possibly give rise to an abnormal distribution of ocular tension.

Adolescent↗
PubMed1979

[Aspects of the development of ocular onchocerciasis in West-Africa after three years of simulium control (authors transl)].

In four rural West-African communities with different degrees of ocular affection the development of ocular onchocerciasis has been evaluated after three years of vector control. In the area of a successful disruption of the transmission the population with a slight degree of ocular onchocerciasis before control operations started, did not show an aggravation of the lesions. In those groups severely affected at the beginning of vector control the lesions showed no progression in the majority of the cases. The diminuition of the ocular parasite load, resulting from the reduced transmission, appears to be an important factor in the change of the incidence of blindness and severe ocular lesions attributable to onchocerciasis. Contrary to this the aggravation of ocular lesions was found to be more severe in a community situated in the area reinvaded by the vector than in those that did not experience a reinvasion of the fly.

Adolescent↗