Poliovirus circulation among schoolchildren during the early phase of the 1992-1993 poliomyelitis outbreak in The Netherlands.

During the 1992-1993 outbreak of poliomyelitis in The Netherlands, we examined 866 childrenat 7 schools for evidence of infection with the outbreak virus, poliovirus type 3(PV3), to determine the extent of the outbreak and the protection of the herd immunity. Seventy-seven children (8.9%) showed evidence of recent wild-type PV3 infection, as determined by virus isolation and/or poliovirus type-specific IgM assay. Most infected children lived in the same area as the index case patient, attended an orthodox-reformed (OR) primary school, and had not been vaccinated. At the OR school, as many as 22% of children immunized with inactive poliovirus vaccine were found to have evidence of recent infection, which is a significantly lower rate than that among unvaccinated children (59.5%). No evidence of vaccination was seen in 25.5%-43.1% of children at OR schools. Seroprevalence of antibodies against the 3 types of poliovirus suggested that no poliovirus circulation had occurred between the 1978 and 1992-1993 outbreaks.

Visceral leishmaniasis control: a public health perspective.

Visceral leishmaniasis (VL), also known as kala-azar, is a vector-borne disease caused by a protozoan of the Leishmania donovani complex. A phlebotomine sandfly transmits the parasite from person to person or via an animal reservoir. VL is a severe, debilitating disease, characterized by prolonged fever, splenomegaly, hypergammaglobulinaemia and pancytopenia. Patients become gradually ill over a period of a few months, and nearly always die if untreated. Case-fatality ratios are high even in treated patients. Worldwide an estimated 500,000 VL cases occur each year. This study reviews clinical, epidemiological and public health aspects of the disease and shows how critical adequate case detection is for the success of VL control. Examination of the issue of VL diagnosis with respect to the global challenges in VL control leads to the observation that a sound diagnostic-therapeutic algorithm for the health services in endemic areas is badly needed. Serological tests could be an alternative to parasitological diagnosis and the direct agglutination test (DAT) was found to fulfil many criteria for a 'field test', including cost effectiveness. Although research needs on vaccine and better drugs continue to be high on the agenda, a VL test-treatment strategy based on currently available highly sensitive serological tests, such as the DAT, should be introduced in the health services in endemic areas.

Food intolerance (food hypersensitivity) and chronic complaints in children: the parents' perception.

UNLABELLED: The aim of the study was to assess the prevalence of food intolerance (FI) in Dutch 5- and 6-year-old children and its association with chronic ailments with a survey among parents by questionnaire. Based on parents' perception the prevalence of "probable" FI was 3.8%. FI was associated with asthma, wheezing, eczema, hay fever, chronic rhinitis, hives, chronic diarrhoea and hyperactive behaviour. The Dutch research results are commensurate with the findings of a study carried out in the U.K. Parents frequently associate FI with eczema, hives, chronic diarrhoea and hyperactivity. The association with FI remains for asthma, wheezing, chronic rhinitis, hay fever, chronic diarrhoea and hyperactive behaviour even after adjustment for this information bias. CONCLUSION: Many parents are not aware that chronic ailments in their child may be caused by FI. The associations of FI and chronic complaints are strong enough to justify the discussion with parents during the client contacts by school physicians, in order to assess the advantages of consulting a paediatrician or allergologist.

[Prevalence of chronic diseases in school children reported by their parents]. / Prevalentie van door ouders gerapporteerde chronische aandoeningen bij schoolkinderen.

OBJECTIVE: To establish the prevalence of chronic diseases reported by parents among a random population of Dutch children. Furthermore, to establish how often these children visited a physician because of a chronic disease, and used drugs for its treatment. SETTING: Dordrecht and environs. DESIGN: Descriptive. METHOD: In the school year 1990-1991, all 8689 parents of school children summoned for a periodical health check by the school doctor or school nurse were sent a questionnaire together with the notification. With the aid of a list of criteria it was determined for every child during the periodical health check if the diseases, if any, were serious, if the children were being treated for them and if they used medication. RESULTS: The response to the questionnaire amounted to 98.3%. Of the children examined, 21.3% according to the parents suffered from one or more chronic diseases, 3.7% to a major extent. Of the group with one or more chronic diseases, 25.2% were monitored by the family doctor, 10.5% by the paediatrician, 18.6% by various other specialists and 4.5% by a homeopathist. Of the population as a whole, 10.1% used medication because of one or several of the chronic diseases; this accounted for 47.4% of the group with one or several chronic diseases. CONCLUSION: The prevalence of chronic diseases in school children reported by the parents is so high that it should be given attention in post-graduate education and public health information.

Serological and virological assessment of oral and inactivated poliovirus vaccines in a rural population in Kenya.

A study was carried out in a rural community in Kenya to compare the humoral and intestinal immunity provided by three doses of oral poliovirus vaccine (OPV) and two or three doses of enhanced-potency inactivated poliovirus vaccine (IPV). The immunization series was started at 8-12 weeks of age and the interval between doses was 2 months. In children with low levels of maternal antibodies (i.e., those most at risk), the first dose of either vaccine stimulated antibody response. Children with high levels of maternal antibodies responded to the first dose of OPV, but not to that of IPV. Subsequent doses led to increases in the mean antibody titres with both vaccines. After three doses of OPV, the proportion of children with antibody titres of greater than or equal to 1:8 was 92% for type 1 virus, 98% for type 2, and 90% for type 3. After two doses of IPV the proportion of children with antibody titres of greater than or equal to 1:8 was 94%, 88%, and 97% for type 1, type 2, and type 3, respectively; after three doses of IPV, 100% of children had antibodies greater than or equal to 1:8 for types 1 and 3, and 98% for type 2. Intestinal immunity was tested with a challenge dose of type 1 OPV, but the dose used was too small to detect a significant difference between the vaccines.

Gender and the pattern of transmission of measles infection. A reanalysis of data from the Machakos area, Kenya.

Data on measles from the project in the Machakos district, Kenya between 1974 and 1981 have been reanalysed in order to test the impact of sex and cross-sex transmission on severity of infection. In families with several cases, the case fatality rate was high as 11.3% (13/115) during the initial 6 months of the project. In the remaining period, the case fatality rate fell to 2.4% (21/885) (relative risk (RR) = 0.21, 95% confidence interval (CI): 0.11-0.39). During the initial period with high mortality, second cases had 4.74 times higher mortality (95% CI: 1.65-13.66) than index cases and there was no difference in mortality between girls and boys (RR = 0.98). Among secondary cases, though not significant, those infected by someone of the opposite sex had a trend toward a higher risk of dying than those infected by someone of their own sex (RR = 2.44, 95% CI: 0.77-7.78). In families with two children of the same sex, the case fatality rate was 9% compared with 29% in families with a boy and a girl (RR = 3.49; 95% CI: 0.96-12.75). In the subsequent period with low mortality, the difference in mortality between index and secondary cases was less pronounced (RR = 2.32, 95% CI: 1.03-5.25) and girls had significantly higher case fatality than boys (RR = 2.63, 95% CI: 1.09-6.34). There was no difference in this case fatality rate associated with cross-sex transmission of infection (RR = 0.88).(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of transmission and severity of measles infection: a reanalysis of data from the Machakos area, Kenya.

Data on measles from the project in the Machakos District, Kenya, 1974-1981, were reanalyzed. In families with several cases, secondary cases (children infected in the home) had a relative mortality risk of 3.00 (95% confidence interval [CI]: 1.55-5.80) compared with index cases who caught infection from someone outside the home. The case fatality rate (CFR) may be higher among secondary cases exposed to two or more index cases than among those exposed to only one index case (relative risk [RR] = 2.47; 95% CI: 0.93-6.56). The CFR was also higher among secondary cases exposed to a fatal index case than among those exposed to an index case who survived (RR = 4.69; 95% CI: 1.64-13.41). Children aged 12-23 months and those greater than or equal to 5 years were more likely than other age groups to have been infected by someone outside the home. During the course of the project the CFR in families with several cases was reduced from 8.8% to 2.7%. Though there is no general explanation for this tendency, it was observed that the proportion of secondary cases per index case was reduced during the last part of the project (odds ratio = 0.73; 95% CI: 0.56-0.95).

Visceral leishmaniasis unresponsive to pentostam caused by Leishmania tropica in Kenya.

We report the characterization of 6 Leishmania tropica isolates from 2 patients with visceral leishmaniasis who were unresponsive to treatment with sodium stibogluconate. The Leishmania isolates, MHOM/KE/81/NLB-029A, -029XIB, and -029XIC and MHOM/KE/81/NLB-030I, -030B, and -030XXA, all from splenic aspirates, were characterized by cellulose acetate electrophoresis using 11 enzymes: malate dehydrogenase, malic enzyme, phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, superoxide dismutase, glutamate-oxaloacetate transaminase, adenylate kinase, nucleoside hydrolase, mannose phosphate isomerase, glucose phosphate isomerase, and phosphoglucomutase. Isozyme migration patterns were indistinguishable from those of 2 WHO reference strains of Leishmania tropica (MHOM/SU/60/LRC-L39, NLB-305 and MHOM/IQ/OO/LRC-L36, NLB-067). These are the first reported cases of visceral leishmaniasis (kala-azar) caused by L. tropica in Africa; these cases were refractory to sodium stibogluconate.

Indigenous human cutaneous leishmaniasis caused by Leishmania tropica in Kenya.

Six Leishmania isolates from 3 indigenous Kenyans (2 isolates from one patient) and 2 Canadian visitors in Kenya were characterized by cellulose acetate electrophoresis. The isolates were compared among themselves and with reference strains of Leishmania donovani, L. aethiopica, L. major, L. tropica, and L. arabica using 9 enzymes: malate dehydrogenase (MDH), malic enzyme (ME), phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), aspartate aminotransferase (ASAT), adenylate kinase (AK), mannose phosphate isomerase (MPI), glucose phosphate isomerase (GPI), and phosphoglucomutase (PGM). Enzyme migration patterns of isolates from the 3 indigenous Kenyans were indistinguishable from those of 2 L. tropica reference strains. The isolates from the 2 Canadians yielded migration patterns of 7 enzymes that were indistinguishable from those of 2 L. tropica reference strains. However, migration patterns of 2 enzymes, PGM and ME, differed from all migration patterns of the 10 reference strains. Balb/c mice were inoculated with stationary phase promastigotes cultured from 3 stabilates from the lesions of 2 of the Kenyan patients. The mice developed no gross pathological lesions in 6 months time. All of the study patients developed cutaneous leishmaniasis while living in or visiting districts in Central and Rift Valley Provinces, Kenya. This is the first report of human cutaneous leishmaniasis caused by L. tropica indigenous to Africa south of the Sahara.

Improvement of a direct agglutination test for field studies of visceral leishmaniasis.

To increase the potential for the wide-scale application of our direct agglutination test for visceral leishmaniasis, modifications in the components and procedures were introduced. Supplementation with 0.056 M citrate of the suspension medium stabilized the antigen for 9 weeks at 37 degrees C. To circumvent the need for cooling systems in the field, 0.2% (wt/vol) gelatin was added to the serum diluent instead of fetal bovine serum, with reliable results. Specificity and sensitivity were improved by the incorporation of 0.1 M 2-mercaptoethanol in samples with borderline titers. The test could be performed on samples of whole blood; thus the difficulties of preparation and storage of serum, plasma, or filter paper blood are avoided. For mass screening programs, a single serum dilution of 1:6,400 could be employed, contributing to a further reduction in test expenses. Sera from different geographical areas showed equal reactivities in this direct agglutination test despite the nonhomologous Leishmania donovani antigens used.

Isolation of Leishmania donovani from Phlebotomus martini in Baringo district, Kenya.

An 18-month sandfly survey was conducted at 4 locations in Baringo District, Rift Valley Province, Kenya. 3 collection techniques were used: aspiration, sticky paper trap, and light trap in sites selected because of their proximity to homes of visceral leishmaniasis patients diagnosed and treated within 6 months before the survey. Over 2000 female Phlebotomus martini were collected of which 6 females were found to have flagellate protozoan infections. 3 of these infections were cultured successfully and cryopreserved. 2 isolates were identified as Leishmania donovani by cellulose acetate electrophoresis. The zymogram of the third isolate was different from all Old World Leishmania reference strains examined, and it is still unidentified. The finding of 2 P. martini naturally infected with L. donovani strongly supports the hypothesis that this species is a vector of visceral leishmaniasis in this area.

Cutaneous leishmaniasis caused by Leishmania tropica in Kenya.

9 leishmanial strains, isolated from cutaneous papulonodular lesions on 3 patients, were characterized by cellulose acetate electrophoresis using 7 enzymes. The patterns obtained were indistinguishable from those of a Leishmania tropica reference strain and these 9 strains were similar to L. tropica in failing to infect mice. Although these 3 patients were Americans, their only potential exposure to sandflies was in Kenya, and thus they are believed to be the first cases of cutaneous leishmaniasis due to L. tropica in Kenya.

Evaluation of a newly developed direct agglutination test (DAT) for serodiagnosis and sero-epidemiological studies of visceral leishmaniasis: comparison with IFAT and ELISA.

A newly developed direct agglutination test (DAT) for visceral leishmaniasis, IFAT and ELISA were applied to sera of patients with visceral leishmaniasis, African and American trypanosomiasis, other parasitic infections and healthy controls. The sensitivities of the 3 tests were comparable (96.3% to 100%); excluding patients with African and American trypanosomiasis, the specificities of DAT and IFAT were 100% and ELISA 87.3%. When trypanosomiasis sera were included, the specificities were 72.6%, 94.3% and 79.4% in DAT, IFAT and ELISA respectively. In 273 sera from a leishmaniasis endemic area (Baringo District, Kenya), the sensitivity was 80% in DAT and IFAT and 60% in ELISA, specificities being 99.6% (DAT), 98.5% (IFAT) and 62.5% (ELISA). As the new DAT is economical and easy to perform, it is recommended for sero-epidemiological field work on visceral leishmaniasis.

Cutaneous leishmaniasis caused by Leishmania major in Baringo District, Kenya.

Leishmania major was isolated from lesions of a patient suffering from cutaneous leishmaniasis in Baringo District of Kenya. Isoenzyme mobilities of this strain were compared with those of L. major, L. donovani, L. aethiopica and L. tropica reference strains and also L. major from a sand fly, Phlebotomus duboscqi, and a rodent, Arvicanthis niloticus, trapped in the same region. The patient's isolate had similar banding patterns to the L. major reference strain and also the rodent and the sand fly strains with the 9 enzymes examined. This is the first report in Kenya of an indigenous case with naturally acquired zoonotic cutaneous leishmaniasis.

A simple and economical direct agglutination test for serodiagnosis and sero-epidemiological studies of visceral leishmaniasis.

A simple and economical direct agglutination test for the detection of visceral leishmaniasis is described. Trypsin-treated, Coomassie Brilliant Blue-stained, formalin-preserved promastigotes were used as antigen in re-usable V-well microtitre plates. In 21 patients with recent kala-azar, titres of 1:51200 or higher were found. Cured kala-azar patients treated 4 to 14 months before testing, showed titres in the range of 1:3,200 to greater than 1:51,200. Healthy and diseased controls had titres below 1:1,600 with the exception of African trypanosomiasis patients who showed titres of 1:200 to 1:12,800, overlapping with the titres of cured kala-azar patients. Where trypanosomiasis is not a consideration, a titre of 1:1,600 could be considered indicative of visceral leishmaniasis, the sensitivity and specificity were then 100%. The test was applied to sera of 280 inhabitants of Baringo District, a known focus of visceral leishmaniasis in Kenya. When treated cases were included, the test showed a sensitivity of 100% and specificity of 99.3%. This test could be used in district hospitals and health centres in endemic areas as an aid in diagnosis of kala-azar and in the field for sero-epidemiological studies.

Pertussis: epidemiology and control.

PIP: Pertussis is a common, highly infectious, respiratory disease that predominantly affects children. As many as 60 million cases with more than a 1/2 million deaths occur annually. The highest incidence rates are observed in developing countries where immunization coverage is low. Accurate diagnosis under field conditions is hampered by current laboratory methods. The control of pertussis is accomplished largely through immunization and improvement of socioeconomic conditions. Although the adsorbed DPT vaccine is associated with some side effects, its benefits outweigh the risks when the vaccine sequelae are compared with the morbidity and mortality caused by the natural disease. Surveillance of pertussis and outbreak investigations provide valuable information about the disease and its effectiveness of ongoing immunization programs. (author's)^ieng