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D Metselaar

Publications and source records attributed to D Metselaar.

At least 19 recordsLinked to original sources
PubMed1980

An outbreak of type 2 dengue fever in the Seychelles, probably transmitted by Aedes albopictus (Skuse).

Between December 1976 and September 1977 the Seychelles group of islands in the Indian Ocean was struck by an extensive epidemic of dengue fever. The peak of the epidemic was in the last week of February. Type 2 dengue virus was isolated from patients and mosquitos. Aedes albopictus was the sole vector. The clinical picture was that of classical dengue. Haemorrhagic fever and the shock syndrome were not observed.Absenteeism from schools and offices, anamnestic questioning, and prevalence of antibodies in sera collected after the epidemic was over, indicated that approximately 75% of the population had been infected. Serological evidence was obtained of an epidemic of dengue in the islands more than 40 years earlier. This was confirmed by archival records.

Adolescent↗
PubMed1978

[Arboviruses].

Explore the source record for details and available documents.

Animals↗
PubMed1978

Agents affecting health of mother and child in a rural area of Kenya. XI. Antibodies against rotavirus in sera from children living in the Machakos District of Kenya.

207 sera from children under 5 years of age and living in the Machakos District in Kenya were tested in the Complement Fixation Test for antibodies against rotavirus. Two different antigens were used. The superiority of 'O' antigen over Nebraska calf diarrhoea virus antigen was confirmed. After a fall to 29 percent in the 6-8 months age group, the percentage of children with antibodies quickly rises with age to 80 percent at the age of 24 months and to practically 100 percent at the age of 30 months. This age-immunity curve suggests that the majority of children contract infections with rotavirus between 6 and 23 months of age. This is conform the pattern usually found in temperate climate countries.

Antibodies, Viral↗
PubMed1978

Poliomyelitis: Epidemiology and prophylaxis. 6. Geographic synchronism in poliomyelitis epidemics in Kenya.

In the 1950s, van Loghem drew attention to what he called "synchronism" in the epidemics of poliomyelitis in western Europe. The 1952 epidemic in the Netherlands affected Belgium and neighbouring parts of the Federal Republic of Germany at the same time. A comparable phenomenon is described from Kenya. Notwithstanding the fact that in the three population concentrations of the country the three poliovirus types may well be endemic, epidemics of poliomyelitis repeatedly occurred synchronously in these areas. However, there seems to be no synchronism between poliomyelitis epidemics in Kenya and those in neighbouring East African countries. Tentative explanations are put forward for the similarities and differences between Europe and East Africa. The importance of the phenomenon as observed in Kenya for control by mass immunization campaigns is stressed.

Humans↗
PubMed1978

Agents affecting health of mother and child in a rural area of Kenya. X. Haemagglutination inhibiting antibodies against influenza A (H3N2) and influenza B virus in sera from children living in the Machakos District of Kenya.

In the framework of the Machakos Project bloodcollections from random samples of children under 5 years of age and living in a rural area of Kenya were done with regular intervals, Serum samples of two collections were tested for haemagglutination inhibiting antibodies against influenza A and B viruses. The children had been exposed to the Hong Kong/1/68 (H3N2) virus or its variants during one, two or three episodes of circulation and probably to only one epidosde of B/Hong Kong/8/73 virus. The results can be explained by the assumption that 30-40 percent of non-immune children were infected per epidosde of exposure to influenza A and not more than 12 percent per episode of influenza B circulation.

Antibodies, Viral↗
PubMed1977

Poliomyelitis: epidemiology and prophylaxis. 4. Serological and virological surveys conducted after a mass vaccination campaign for the control of a threatening poliomyelitis epidemic.

In 1973, a type 1 poliomyelitis epidemic in Kenya was curtailed at an early stage by two mass distributions of trivalent oral vaccine. It was considered useful to know the immunity status of the child population that had resulted from the vaccine distributions and that had presumably contributed to its control. We also wished to know to what extent wild and vaccine virus strains were in circulation after the mass vaccination campaign. Anal swabs and blood were collected from a sample of the children in four areas where the efficiency of vaccine distribution had varied, and the results of virus isolation attempts and antibody tests are reported. Three poliovirus strains were isolated. It was surprising that, in general, the herd immunity after two vaccination rounds did not substantially differ from that found in Kenya on other occasions. Possible reasons for these results are discussed.

Age Factors↗
PubMed1977

Poliomyelitis: epidemiology and prophylaxis. 5. Results of a two- and three-dose vaccination experiment.

In tropical countries, seroconversion rates following oral poliomyelitis vaccination are frequently unsatisfactory. In an area of the Machakos district in Kenya, 4000 children under 5 years of age have been registered and are visited fortnightly by trained field staff as part of a comprehensive, population-based, longitudinal surveillance project. It was considered possible that poliomyelitis vaccine, given orally to children twice or three times at home, would produce satisfactory conversion rates. After collection of blood from a random sample of the children, vaccine was given twice to all children under 5 years of age. Blood was then collected a second time from a different sample of children. After a third dose of vaccine, a third blood collection followed. The percentages of the children that received vaccine each round were calculated and the sera tested for antibodies. It appeared that the mean titre was more strongly related to age than to the number of doses of poliomyelitis vaccine received. Improvement of herd immunity after two vaccine distributions was significant for a few age groups and for two types of vaccine only. In none of the groups was a significant improvement obtained by the third vaccine distribution. The problems associated with vaccination by live poliomyelitis vaccine in tropical countries are discussed in relation to the results.

Age Factors↗
PubMed1976

Possible selection of virulent poliovirus strains in Third-World countries.

In Kenya for more than twenty years a remarkable periodicity has been observed in the circulation of type-1 poliovirus and in epidemics of poliomyelitis caused by this virus type. Periodicity was less obvious for poliovirus types 2 and 3. Cases of poliomyelitis increased, and this trend was only partly controlled by vaccination. It is postulated that virulent strains of poliovirus became dominant because of selection pressure. It is suggested that this selection pressure occurred earlier in economically developed countries and was partly responsible for the pronounced changes in the epidemiology of poliomyelitis seen in such countries.

Age Factors↗
PubMed1976

Acute haemorrhagic conjunctivitis and enterovirus 70 in Kenya.

The pandemic of acute haemorrhagic conjunctivitis that started in Ghana in 1969 and spread to many countries in Africa, Asia and Europe reached Kenya in April 1971. From one patient virus was isolated. This was possibly the first strain ever isolated of Enterovirus 70. Identification took time and was finished long after the publication of isolation of the new virus in Japan. Cross neutralization tests with the virus from Japan showed close relationship between the two. During a second epidemic in Kenya in 1974 many more strains of the virus were isolated. The history of isolation and identification and the clinical picture of the disease as seen in Kenya are described.

Acute Disease↗
PubMed1975

An epidemiologic and serologic study of arboviruses in Lake Rudolf basin.

An epidemiologic and serologic study of arboviruses was done in 1972 in the basin of Lake Rudolf. The main object of this study was to demarcate the southern limit of the yellow fever epidemic which occurred from 1959 to 1962 in Southern Sudan and Ethiopia. Other purposes were to contribute to the inventory of arboviruses and their distribution in this region. The ethnic groups were studied: the Nyangatom and the Dassanetch in Ethiopia and the Turkana in northern Kenya. The results of tests on sera of the Nyangatom and the Dassanetch are practically identical: a high percentage of positive tests for group B. The Turkana on the other hand show a low percentage of positives. This is attributed to differences in the climatic characteristics of the two regions. The serological results suggest the presence of West Nile virus in the geographical areas inhabited by the three ethnic groups. The presence of Wesselsbron and probably Uganda S virus is suspected. Circulation of these viruses could be explained by the presence of Culex univittatus and other mosquitoes. As for yellow fever, the results suggest that the virus did not reach the areas studied, probably because of absence of efficient vectors.

Antibodies, Viral↗