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Biomedical subjects

G De Sole

Publications and source records attributed to G De Sole.

29 records · Page 2Linked to original sources
PubMed1989

A community trial of ivermectin in the onchocerciasis focus of Asubende, Ghana. I. Effect on the microfilarial reservoir and the transmission of Onchocerca volvulus.

A community trial of the microfilaricide ivermectin was undertaken in an isolated focus of hyperendemic savanna onchocerciasis in Ghana. One of the objectives was to determine the effect of mass treatment on the microfilarial reservoir and on the transmission of Onchocerciasis volvulus. Since 1978 the focus has been under entomological surveillance. This was intensified from 1 September 1987 till 11 February 1988 with daily vector collection and dissection of over 30,000 flies. A total of 14,991 people were treated with ivermectin on 7-10 October 1987. Skin snip surveys were done pre-treatment, and at two and four months after treatment. The mean skin microfilarial load in treated persons had fallen by more than 96% two months after treatment. During the next two months there was an increase in microfilaria loads which appeared to be faster than reported in the clinical trials. The total reservoir of skin microfilariae available for transmission had been reduced by an estimated 68%-78% two months after treatment. This was consistent with the entomological results which indicated a reduction in transmission of 65%-85% during the first three post-treatment months. The present study has shown for the first time that mass chemotherapy can significantly reduce onchocerciasis transmission. However, the remaining level of transmission was still unacceptably high and further studies are required to predict the long term impact of repeated mass treatment.

Animals↗
PubMed1989

A community trial of ivermectin in the onchocerciasis focus of Asubende, Ghana. II. Adverse reactions.

A community trial of the microfilaricide ivermectin undertaken in an hyperendemic focus of blinding onchocerciasis in Ghana. One objective was to investigate the safety of this new drug when used in mass treatments. 14,911 persons (61.5% of the census population) were treated with ivermectin. Of these, 15% reported with adverse reactions which were generally similar to those reported in the clinical trials. However, cutaneous reactions were relatively less frequent while brawny oedema of the limbs and inguinal gland pain were important. The severe reactions consisted of 37 cases of Severe Symptomatic Postural Hypotension (SSPH), 13 cases of severe fever and two cases of severe dyspnoea. The latter two cases represented life threatening situations, but there was no evidence that they were complications of ivermectin treatment. Only four of the SSPH cases required treatment. All severe adverse reactions were managed successfully and recovered within one day, usually within a few hours. The incidence of adverse reactions was highest the first day after treatment. Thirteen cases of delayed reactions were reported during a four-week follow-up. There was a highly significant relationship between incidence of adverse reactions and intensity of infection but no relation with ivermectin dosage within the range of 130-200 mcg/kg. The results suggest that ivermectin is sufficiently safe to be used in mass treatments. However, mass distribution of this drug should not be undertaken without adequate monitoring.

Adolescent↗
PubMed1989

Adverse reactions after large-scale treatment of onchocerciasis with ivermectin: combined results from eight community trials.

Eight community trials were carried out by the Onchocerciasis Control Programme in West Africa to determine the safety of the new microfilaricide ivermectin during large-scale treatment of onchocerciasis. The trial areas were located in eight different countries and varied greatly in endemicity level; a total of 50,929 persons were treated and monitored for 72 hours. Overall treatment coverage was 60% of the census population, the main reasons for non-treatment being the exclusion criteria. Of those treated, 9% reported with adverse reactions, 2.4% with moderate reactions, and 0.24% with severe reactions. Most reactions were reported during the first day of follow-up, the most frequent severe reaction being severe symptomatic postural hypotension (in 49 cases). Three cases of severe dyspnoea were life-threatening but their relationship with ivermectin treatment is uncertain. The incidence of adverse reactions was directly related to skin microfilarial load and was highest in the foci with the highest endemicity levels. Treatment resulted in 98% reductions in mean microfilarial loads at all endemicity levels. The benefit of treatment largely compensated for the discomfort due to adverse reactions, which were all transient and managed successfully. Ivermectin thus appears to be sufficiently safe for large-scale treatment but monitoring by resident nurses for at least 36 hours is recommended.

Africa, Western↗
PubMed1988

Test of the prevention of blindness health education programme for Ethiopian primary schools.

Trachoma is a major cause of blindness in Ethiopia and is widespread throughout the country. No health education for blindness prevention is conducted in schools even though 62% of the eligible children attend primary school. Because of the low cost and potential benefit of such a strategy, we developed a programme of health education for eye infections targeted to primary schools and tested it in the rural town of Metahara. Students were given examinations before and after the programme. Their knowledge improved from a mean score of 4.3/9 to 6.2/9 (p less than 0.005). The prevalence of moderate and severe Trachoma decreased from 12.1% to 3.3% (p less than 0.001) in one year, and the prevalence of conjunctivitis from 7.5% to 0.4% (p less than 0.001). Health education for the prevention of blindness in primary schools should be a priority in Ethiopia and yearly eye examinations of school children by local health staff should be reinstated.

Blindness↗
PubMed1987

Vitamin A deficiency in southern Ethiopia.

In Arsi and Bale regions of Ethiopia we found an area in which vitamin A deficiency is hyperendemic and linked to monocrop grain farming. The prevalence of mild xerophthalmia is higher in villages than settlements and higher in settlements than towns (p less than 0.001 for both). The prevalence of mild xerophthalmia is higher in males than females (p = 0.03) and the difference cannot be explained by ecological factors. Nutritional status, length of weaning, severe diseases, and intake of food with low-vitamin A content are factors associated with vitamin A deficiency. Length of weaning and severe diseases play a more important role than nutritional status in this study. The prevalence of diarrhea and respiratory diseases was twice as high in children with xerophthalmia than in children without (p less than 0.001 and less than 0.02, respectively). The incidence of measles was higher in children with vitamin A deficiency than in children without, relative risk 4.7 (p = 0.01).

Agriculture↗
PubMed1987

Impact of cattle on the prevalence and severity of trachoma.

Ethiopia is the African country with the largest number of cattle (26 million). Because of the potential impact of cattle on the transmission and severity of trachoma, the major cause of blindness in the country, an attempt is made to document this association to justify the inclusion of the control of cattle pollution in the prevention of blindness. The prevalence of trachoma is lower in pastoralists who herd mainly camels than in pastoralists who herd mainly cattle. In the first group the prevalences of moderate and severe trachoma in children under 10 are 0.9% and trichiasis/entropion in the total population 0.2%, whereas in the second group the prevalences are 45.1% and 4.0% respectively. In Borana pastoralists with and without cattle the prevalence ratio for moderate and severe trachoma is 1.0, whereas the prevalence ratios for severe trachoma and conjunctivitis were higher in the group with cattle, 2.5 and 3.0 (p less than 0.001 for both). The elimination of cattle pollution should reduce the prevalence of severe trachoma by 45.4%. This is the first study presenting evidence of an association between cattle and trachoma. On the basis of this study a strong recommendation is made to the Ministry of Health to control cattle pollution in rural areas as a major strategy to prevent blindness in Ethiopia.

Animal Husbandry↗
PubMedDate not supplied

Changes in ocular onchocerciasis after two rounds of community-based ivermectin treatment in a holo-endemic onchocerciasis focus.

In a longitudinal study to determine the effect of annual community-based treatment of ocular onchocerciasis with ivermectin, the population living in the 3 most affected villages in the holo-endemic onchocerciasis focus of Asubende in Ghana were re-examined 16 and 24 months after initiating treatment. Ocular microfilarial loads had decreased to very low levels in nearly all of the 334 examined persons who were treated twice. Only very few subjects had ocular loads of 32 microfilariae or more in the anterior chamber of the eye, but this was not associated with deterioration of ocular lesions. Important regression of both early and advanced lesions of the anterior segment of the eye was observed, which was highly statistically significant with respect to iridocyclitis. Lesions of the posterior segment of the eye remained stable. Though no systematic change in the visual acuity of the population was observed, 3 new cases of blindness occurred in persons who already had eye lesions at such an advanced stage that ivermectin treatment could no longer affect the outcome. The results suggest that annual ivermectin treatment is adequate to control onchocercal ocular disease even in populations with very high endemicity levels.

Adolescent↗
PubMedDate not supplied

Onchocerciasis infection in children born during 14 years of Simulium control in West Africa.

The incidence of onchocerciasis infection in children born since the start of vector control is one of the indicators used in the epidemiological evaluation of the Onchocerciasis Control Programme in West Africa (OCP). Though initially of littel value, after a decade of control it has become a sensitive indicator of residual transmission. The results of 14 years of control are reported. In 179 villages parasitological surveys were undertaken at intervals of 3-4 years. 15,286 children were examined and 110 were found to be infected, compared to an expected number of 2467 infected had there been no control. There was considerable geographical variation in the results. In the large central OCP area the results were excellent. Of 12,172 children examined in 127 villages, only 23 were found to be infected compared to an expected number of 1960 without control. This suggests that larviciding had achieved a 99% reduction in the incidence of infection in children. Additional surveys in 2 foci in the central OCP area where transmission had relapsed showed that these problems were very localized. Most villages with infected children were found in OCP border areas in the east and west, which had been reinvaded by infective vectors from elsewhere, and in the intermediate area between forest and savanna in Côte d'Ivoire where there had been partial control failures because of resistance. The incidence of infection in children was reduced by an estimated 68% in the eastern reinvaded area, by 87% in the western reinvaded area, and by 84% in the intermediate area.

Adolescent↗
PubMedDate not supplied

Criterion for inclusion in onchocerciasis control programmes based on ivermectin distribution.

Data on onchocercal lymphatic and skin lesions from 45 communities located in the West African savanna were analysed to determine if the criterion for inclusion in ivermectin mass treatment based on risk of onchocercal blindness needs to be modified. Only 16 cases of elephantiasis were reported among 10,108 people examined. Other lymphatic lesions were almost exclusively found in people older than 30 years living in villages at risk of onchocercal blindness. Permanent skin lesions also affected older people and were 3 times more frequent in villages at risk of onchocercal blindness. Papular rash and pruritus affected younger people. No evidence was, therefore, found to change the criterion based on risk of onchocercal blindness presently in use in savanna areas.

Adolescent↗
PubMedDate not supplied

Transmission patterns of onchocerciasis in southwest Ethiopia.

The three transmission patterns found till now in Ethiopia are described. The forest area contains ideal conditions for the breeding of Simulium, but the sparse human population makes the transmission rate low. Only a few people were found to be infected. The subsistence crop farming area is a less ideal habitat for the vector due to the scarcity of bush and shade. However the presence of a largest population can explain the slightly higher prevalence of the disease than in the forest. The coffee farming area is densely populated, rich in bush and shade, with heavy rainfall and numerous rivers. Here the number of Simulium and their chance to reach the infective stages, are considered to be high. A high prevalence of the disease was found in this zone.

Adolescent↗