Showing papers by "World Health Organization published in 1985"

Etiopathogenesis of the rheumatoid arthritis-like disease in MRL/l mice. I. The histomorphologic basis of joint destruction.

Abstract: MRL/l mice spontaneously develop a hindlimb arthropathy, as well as a number of immunologic abnormalities, including circulating rheumatoid factors. Although previous studies have suggested that this arthropathy is primarily an inflammatory process, we performed a comprehensive histomorphologic study which indicated that inflammation is a late manifestation of MRL/l arthritis. The pathologic changes that occur in the joints of these mice can be divided into 3 stages. The first stage develops between the ages of 7 and 13 weeks and consists of synovial cell proliferation in the joint recesses. The second stage is characterized by continued proliferation of synovial cells which take on an appearance similar to that of transformed mesenchymal cells. The earliest destructive changes occur in the second stage and include marginal erosions, followed soon after by progressive destruction of articular and meniscal cartilage. The final stage is characterized by a diminution of synovial cel proliferation, extensive cartilage destruction, formation of scar tissue and fibrocartilage, and a very moderate infiltration of the synovial stroma by mononuclear and polymorphonuclear inflammatory cells. Throughout the disease progression there is a striking dissociation between inflammatory cell infiltration or exudation and tissue destruction. The histomorphologic similarities between human rheumatoid synovitis and the arthritis of MRL/l mice, as well as the presence of rheumatoid factors, make this mouse strain an excellent model for studying human rheumatoid arthritis.

The Control of Endemic Treponematoses

Abstract: During the 1950s and 1960s following a decision by the 2nd World Health Assembly in 1949 mass treatment campaigns against the endemic treponematoses were undertaken with the support of WHO and the UN Childrens Fund. The control policy was based on recognition of the importance of: 1) screening at least 90% of the target population; 2) conducting periodic resurveys and treating missed new and imported cases; 3) treating the entire treponemal reservoir (including latent cases and contacts); and 4) using adequate dosages of long acting penicillin (minimal dosages were recommended). Later on policies on the extent of contact treatment at different levels of endemicity were established. During these mass campaigns approximately 50 million clinical and latent cases and contacts were treated; prevalence of endemic treponematoses was reduced dramatically. The major reasons for resurgence of yaws and endemic syphilis in some areas are discussed. One important factor has been the failure of many countries to integrate active control measures into local health services after the mass campaigns. Yaws and pinta are continuing to decline to very low levels in the Americas. In West Africa especially the incidence of yaws and endemic syphilis have returned to high levels. Few significant endemic areas remain in Asia except in Indonesia and Papua New Guinea. (authors)

Drug-resistant malaria--changing patterns mean difficult decisions.

Abstract: Historique et geographie du paludisme resistant aux antimalariques. Carte de la repartition geographique actuelle. Facteurs influencant le developpement de cette resistance. Mesure de la resistance au traitement de Plasmodium falciparum, in vivo et in vitro; etude longitudinale au Kenya

Rabies in the Tropics — History and Current Status

Abstract: Rabies, a disease of antiquity, continues to persist as a major public health problem in this age of high technology. Despite significant scientific breakthroughs and advances in its prevention and control, rabies remains one of the most dreadful and gruesome of the human communicable, infectious diseases. In fact, in the last decade, the gap has widened between available technology and knowledge to prevent and control the disease and their application for the benefit of the general population, particularly in the poor developing countries.

Physiological indicators of fluoride exposure and utilization: an epidemiological study.

Abstract: Individual samples of urine, fingernails, head-hair, saliva, plaque and enamel were collected from three groups of Hungarian children, aged 14 years, who were exposed to contrasting water fluoride levels (less than or equal to 0.11 ppm; 0.5-1.1 ppm; 1.6-3.1 ppm). The mean fluoride concentration of the samples increased consistently and significantly, but mostly non-proportionately, with increasing water fluoride level. With the exception of plaque, the materials examined are considered suitable indicators of exposure to or systemic utilization of fluoride for population groups. Caries experience decreased with increasing fluoride exposure. Dental fluorosis constituted no clinical or aesthetic problem.

Rubella--world impact

Abstract: Worldwide, rubella is considered a public health problem because of the risk of infection to the fetus and of subsequent congenital defects. It is not a notifiable disease in most countries, and even where it is, it is underreported, and greater than 50% of infections are clinically inapparent. The impact of rubella is therefore gauged mainly through seroepidemiologic studies. Rubella appears to be endemic worldwide except in some remote areas or islands, where explosive outbreaks may occur. In general, a large proportion of a population is infected before puberty, but approximately 20% of adults may remain susceptible. Effective vaccines against congenital rubella exist, and many countries have already begun or are considering initiating large-scale immunization programs. In the developing world, where problems compete for priority in the mobilization of meager available resources, certain factors need to be considered before such programs are launched, including the ability to effectively deliver a program, the relationship between susceptibility and the age-fertility pattern, the incidence of congenital rubella, and the cost-effectiveness of intervention.

The pros and cons of modelling malaria transmission.

Abstract: The question is approached through three examples. Ross's model, although very simple and formulated a priori, yielded important epidemiplogical insights: the existence of a threshold contact rate (vectorial capacity); the decreasing sensitivity of the endemic level to changes in the contact rate, as the latter gets larger; the return to the same equilibrium endemic level, as long as the contact rate remains the same; the progressively decreasing impact of a given reduction in the contact rate until a new equilibrium is reached. The second example is Macdonald's model, in particular his sensitivity analysis; two constraints are pointed out: the weakest point, on which to concentrate control efforts, cannot be identified automatically by the sensitivity analysis; the calculation of the expected impact of an intervention commonly assumes too much uniformity (e.g. of human of vector behaviour) and this commonly leads to exaggerated expectations. The third example is the Garki model, briefly considered in terms of its assumptions, of its behaviour, of its actual utilization (only for teaching, so far), and of the cost of its development. Looking forward, three uses of models are discussed. It is suggested that, critically used, they have a place in training, in planning control and in research. With respect to their application to planning, it is argued that the need for new data is not necessarily great, also that some rather difficult direct measurements might be substituted by indirect measurements, a point illustrated by the expected relationships, following the Garki model, between different dimensions of “intensity” of malaria. With respect to research, it is suggested that simulations may assist in clarifying discussions around the expected impact of malaria vaccines, hence guide their field testing.

Oral examinations in medical education.

Abstract: A questionnaire survey was conducted on the nature of the oral examinations in different disciplines in the medical schools in Sri Lanka A total of 352 students from Peradeniya and Jaffna medical faculties and pre-registration house officers, including Colombo faculty graduates of the two teaching hospitals, responded to the questionnaire The results of the survey, which included twelve disciplines, reveal that the time duration of the oral encounter ranged from 10 to 20 minutes The number of questions asked ranged from five to nine Detailed analysis of the intellectual level of the questions showed that more than 63% of the questioning was at simple recall level and none at the level of problem-solving These results show that the oral examination in addition to its inherent weakness of low reliability and objectivity also lacks validity in terms of content sampling Its predictive validity of professional competence, which requires problem-solving skills, is questionable Content analysis of the items also revealed that all the abilities tested in the orals could best be tested in a pen-and-paper examination or a structured practical or clinical examination

Headache in the rural village of Quiroga, Ecuador

Abstract: SYNOPSIS Epidemiologic studies on headache among the Mestizo population in the rural village of Quiroga, Ecuador, was carried out as part of a neuroepidemiologic project under sponsorship of the World Health Organization. The distribution and prevalence of headache according to age and sex taken from a sample of 1113 persons is reported. Of the total number of headache sufferers, 35% gave a history of only occasional headache; these were equally divided among males and females. The remainder or 65% regarded their headaches as severe or disabling; 81% were female. Of these, 43% described migrainous headaches. Among the males the headache classification was 77% tension-type and 23% migrainous. The overall prevalence of migraine (both common and classical) was 11/1000 for males and 61.5/1000 for females. In a preliminary investigation of the association of headache and depression, 63% of 19 female sufferers scored clearly in the depressed range.

Changing Patterns in Suicide Behaviour

Abstract: Suicide is one of the most common causes of death and among young people it ranks among the first in many countries of the European Region. The World Health Organization (WHO) considers suicide and attempted suicide as serious public health problems.

Maternal-child hepatitis B virus transmission in Singapore.

Abstract: A study of maternal-infant transmission of hepatitis B virus (HBV) was conducted in Singapore between June 1980 and June 1982. HBsAg carrier rate was highest among Chinese (6.2%) followed by Malay (2.3%) and Indian (0.6%) mothers. The presence of HBeAg in maternal sera correlated well with high titre HBsAg (p = 7.34 X 10(-5)). Overall HBV transmission occurred in 27/56 (48.2%) infants from carrier mothers. The majority of the transmission was perinatal. There was a very strong correlation between transmission and HBeAg status of the mother (p = 1.85 X 10(-9); odds ratio = 68.44) and to a lesser extent with high titre HBsAg (p = 0.002; odds ratio = 6.38). A strong negative correlation was seen between transmission and anti-HBeAg (p = 8.19 X 10(-7); odds ratio = 0.04). At one year 19 (70.4%) infants were still HBsAg positive while seven (25.9%) lost the antigenemia and acquired anti-HBsAg and one developed HBsAg after one year. It could be calculated that perinatal HBV transmission contributed about 18% to the total pool of HBsAg positive infants of one year of age.

Effect of praziquantel on hematuria and proteinuria in urinary schistosomiasis.

Abstract: In five settlements on Lake Volta, Ghana, 230 persons infected with S. haematobium were treated with either 30 or 40 mg/kg of praziquantel. Both treatment regimes gave similar overall cure rates (60%) and reduction in geometric mean egg counts (92%) at a six-month follow-up. In this highly endemic area, 32% of the initial urine specimens were visibly bloody and only 4% remained bloody after treatment. Geometric mean egg counts of visibly bloody urine specimens were two to six times higher than normal appearing urine specimens. In children under 15 years of age, gross hematuria was reduced by 91% and hematuria as detected by reagent strips was reduced by 77% after treatment with praziquantel. Among adults, gross hematuria was reduced by 76% and hematuria as detected by reagent strips was reduced by 68%. Reduction was observed in 74% of all persons with 100 mg of protein/100 ml of urine or more prior to treatment. The cure rate with praziquantel was only 36.1% in children who had visibly bloody urine specimens associated with high geometric mean egg counts prior to treatment. The lowest cure rate (15.4%) was observed in persons with persistent hematuria and proteinuria after treatment although the geometric mean urinary egg count was reduced 84%. In infected individuals without hematuria or proteinuria prior to treatment, the cure rate was 96%. This study demonstrated that praziquantel reduced clinical signs due to S. haematobium infection as well as achieved a high cure rate and/or reduction of egg excretion. Conversely, individuals with clinical signs of hematuria and proteinuria had a lower cure rate with praziquantel than individuals without clinical signs.

Surveillance and control of resurgent yaws in the African region.

Abstract: Yaws, once one of the most common infections in Africa, was expected to be eliminated in some countries and controlled in others after the mass treatment campaigns sponsored by the World Health Organization and the United Nations Children's Fund during the 1950s and 1960s and the implementation of improvements in education, sanitation, and other health-promoting activities. However, the curtailment of yaws control activity allowed the reservoir of untreated yaws to grow unchecked, and the number of reported cases of active yaws has increased in certain parts of Africa, especially in West Africa. In the Central African Republic, the prevalence of yaws is notably high among the Pygmies. Renewed programs for yaws control are under consideration. Mass campaigns are still necessary in some developing countries for the control of certain diseases but should be complementary to the development of general health services and should not be limited to the administrative borders of a given country. Yaws was once one of the most common infections in Africa. It was a major cause of disability and mutilation, especially in rural areas. The World Health Organization (WHO) proposed and carried out in the 1950s and 1960s mass penicillin treatment campaigns in various yaws-endemic areas of the world, including many in Africa. The standard control methods that were developed proved to be enormously successful, the prevalence of yaws decreased dramatically, and in some countries the dis

Development of Trachoma Control Programs and the Involvement of National Resources

Abstract: Trachoma, one of the commonest eye diseases in developing countries, is associated with adverse living conditions and low socioeconomic status. The control of trachoma as a blinding disease has been the target of many national campaigns. The strategy of such campaigns has usually been based on intermittent topical treatment on a mass or selective basis, together with services for trichiasis surgery and health education. National campaigns against trachoma have often been successful on a short-term basis but have not always achieved their long-term goals. Sustained efforts are needed to maintain trachoma control, an area of endeavor that lends itself well to integration with general health services, particularly on a primary health care basis. In addition to logistic aspects, treatment compliance and behavioral patterns related to living conditions must be considered in the design of trachoma control programs.

Molecular epidemiology of human rotavirus infections.

Abstract: Recognition of rotaviruses as a major aetiological agent of acute gastroenteritis in infants and young children has prompted the investigation of their epidemiology by molecular techniques. Genome analysis by electrophoretic separation of the RNA segments has been widely used to distinguish virus isolates and to monitor patterns of virus transmission. Examination of virus isolates from different epidemics has clearly demonstrated the existance of extensive genomic variation in viruses circulating in large communities; with the co-circulation of a number of viruses of differing electrophoretype. Preliminary studies using the more advanced techniques of oligonucleotide mapping and hybridization analysis have suggested that variation among the viruses may occur by processes involving both ≪ drift ≫ and ≪ shift ≫. Because of their ease and specificity the new hybridization analysis techniques should greatly facilitate both the rapid diagnosis of rotavirus infections, and the solution of many epidemiological and evolutionary questions. Continued and expanded use of molecular techniques for the study of the epidemiology of rotavirus infections will be required to manage future outbreaks and to effect long term control measures.

Yaws in Southeast Asia: An Overview

Abstract: A summary is presented of yaws control programs, from their initiation up to the present, in India, Indonesia, and Thailand. In all three countries, the prevalence was spectacularly reduced. From 1950 to 1961, in Java and Bali the rates fell from 11.34% to 0.72%, and comparable results were achieved in India and Thailand. In all programs, resurveys were carried out after the original mass treatment campaigns, and quite successful efforts were made to integrate the yaws control activities into more general health services. Although a small number of active cases of yaws in localized foci are still found, with the rapid expansion of primary health services and continuing surveillance for yaws and the appropriate use of selective or juvenile mass treatment approaches, it should be possible to achieve eradication in the foreseeable future.