PREVALENCE OF STREPTOCOCCAL PHARYNGITIS AMONG SCHOOL CHILDREN OF POKHARA VALLEY , NEPAL

Group A Beta Haemolytic Streptococcal (GABHS) infections and their sequelae Rheumatic fever (RF) and Glomerulonephritis (GN) have a world wide distribution and pose an important health problem. Present study intended to find out the prevalence ofGABHS pharyngitis among school children in the Pokhara Valley, Nepal. It was a cross sectional, observational study. During 7 months period total 750 children were examined from six government primary schools. 25.3% were found to have symptoms of clinical pharyngitis and the prevalence of GABHS pharyngitis was 7.2% among these school children. GABHS pharyngitis found more among male and in the age group of 3-10 years. This study was undertaken to highlight the problems of GABHS throat infections in Nepalese school children and also to stress on the urgent need for control programme for streptococcal disease complex.


INTRODUCTION
Group A beta-hemolytic streptococci (GABHS ) are the usual cause of acute streptococcal throat infection, either pharyngitis or tonsillitis, in children between 5-15 years.Such infections can lead to the late or non-suppurative sequelae, namely, rheumatic fever (RF) leading to RHD and acute post-streptococcal glomeronephritis (AGN ). 1 RF and AGN are major health problems in the developing world.The incidence ofRF declined in industrialized countries, since the 1950's and now has an annual prevalence of 0.5 cases per 1,00,000 children.In developing countries it remains an endemic disease with annual incidence ranging from 100 to 200 per 1,00,000 school children and is a major cause of cardio-vascular mortality. 2RF is reported to occur in 1-3 percent of streptococcal throat infections of children living in underprivileged conditions. 3ABHS are normal inhabitants of the oropharynx and skin.Colonization of the throat with GABHS may occur in 10%-20% of normal school aged children.These children are carriers and do not get actively infected nor are at risk of developing RF. 4 However, throat culture is the most useful laboratory aid in the microbiological diagnosis of acute tonsillitis or pharyngitis especially when blood collection for antibody studies become problematic.Thus in the presence of clinical symptoms of pharyngitis, throat culture becomes mandatory for instituting primary penicillin prophylaxis.
In Nepal, there is no school survey program for the control of RF now, nor there is such a program, being planned for the future either.To initiate a control programme, data on the prevalence and incidence of GABHS pharyngitis are required.However only scant information is available in Nepal regarding the magnitude of this problem.Therefore, a study was carried out to determine the prevalence of GABHS pharyngitis among school children in the Pokhara Valley.

MATERIALS AND METHODS
A cross-sectional study was conducted from Jan-July2001 in six government primary schools in the northern part of Pokhara valley, Nepal.All children were examined for signs of tonsillitis and pharyngitis.Those with positive signs of pharyngitis and/or tonsillitis, history of sore throat and not receiving any antibiotics in the preceding two weeks, were selected for taking throat swabs.The tonsillar and pharyngeal mucosa were rubbed vigorously with sterile cotton swab applicator avoiding the surrounding tissues.The throat swabs were inoculated onto sheep blood agar in the Microbiology Laboratory at the Manipal Teaching Hospital (MTH) and incubated for 24 hours.Beta hemolytic colonies were identified as streptococci by Gram stain and confirmed as GABHS by bacitracin sensitivity.All children were also examined for other infections, and demographic/ anthropometric data were collected.Penicillin prophylaxis was given for those children who were found to be positive for GABHS.After 3 weeks they were followed up in their houses, to detect any sign of rheumatic fever and rheumatic heart disease.

RESULTS
A total of 750 children from six primary schools were examined (Table I).These primary schools covered Kindergarten to 5th standard.Two schools namely, Gyan Bhumi Primary School and Bal Jyoti School accounted for 309 of the 750 children.Girls (n = 383) outnumbered the boys (n = 367) in four of the six schools.Antibody studies are microbiologically important, both for documentation of GABHS pharyngitis as well as a clinical diagnosis of RF/RHD.We were unable to perform antibody studies on children with GABHS pharyngitis for fear of compliance.This is one of the first few school-survey studies carried out in this region and therefore, we wanted to develop a good rapport with the children before we could do intensive studies among them.The present study shows a high prevalence rate of GABHS pharyngitis among school children.Many studies have shown a high carrier rate among school children residing in communities' endemic for GABHS infections.Since our primary objective was only to determine the prevalence of GABHS pharyngitis among these children, we did not do carrier state studies among them.
This study presents high prevalence of GABHS positive cases among male and in the age group of 3-10 years, which is comparable to the findings of similar studies conducted in different parts of world.In this study, RF cases were not detected during follow-up; this might be either due to implementation of penicillin prophylaxis for GABHS positive cases or might be due to the inadequate sample size studied.It is a wellrecognized fact that occurrence ofRF is only to the extent of 1-3% of streptococcal infection.
Our study shows that the prevalence of GABHS pharyngitis in developed countries does not differ from other developing countries.RF and RHD have declined significantly in North America and Western Europe. 10This decline can be attributed to improved socio-economic status, adequate penicillin prophylaxis, development of physical barriers to the spread of streptococci, and less  11 In India, a streptococcal reference system has already been established and primary prevention method for RF and RHD, namely control of streptococcal infections, is also going on. 11Similar control programs should be actively employed to prevent the high prevalence of GABHS pharyngitis and their sequelae.

CONCLUSION
Prevalence of Group A beta hemolytic streptococcal from the throat of symptomatic Nepalese schoolchildren has been reported for the first time.Further epidemiological studies on streptococcal disease complex are needed to substantiate the findings of the study.As methods for streptococcal control progamme have now become cost effective, such programme should be incorporated into any prevention methods for control of RF and RHD, and children below 11 years may require a special attention regarding prevention of streptococcal infection.