Typhoid fever is caused by the bacteria Salmonella Typhi and Salmonella Paratyphi. Due to ingestion of food and water usually contaminated by urine or feces of infected carriers. Typhoid fever is life threatening systemic illness and a major public health problem in many countries including Nepal. Likewise, it is an acute and invasive infection of the gastro intestinal system. This disease is more prevalent in children and young adults 1.

In Nepal, typhoid fever is common in all populated areas. In recent years, increased urbanization, and growing population density within the major cities and the widespread lack of access to clean water and food have lead to a high prevalence of typhoid through out the country 2. In Nepal typhoid fever, commonly known as bisham jwar. It is prevalent in mountains,valley and southern terai region as an endemic. Its peak incidence occuring from from May to August. In Nepal salmonella serovar is the most common single pathogen isolated in blood cultures.

Prior reports from Kathmandu link low socioeconomic status and unsanitary living condition to higher prevalence of typhoid fever. The disease is characterized by prolonged fever, abdominal distension, constipation, headache, rash, malaise, loss of appetite, nausea, vomiting and leukopenia. 3

Approximately, 10% of patients recovering from typhod fever excrete Salmonella Typh in the stool for three month and in the past 2 to 3% become permanent carrier. These infections have great potient for epidemic spread therefore

The study subjects was suspected typhoid fever patients visiting in Nepal Medical College, jorpati. In this study, total 400 blood samples were proceed both from out patients and inpatients visiting in hospital. In this study, male population were more infected (60%) than female population (40%) (Table 1). Likewise, in total isolated cases (200) of Salmonella spp, Salmonella typhi (180) was more prevalent organism than Salmonella paratyphi A (Figure 1).

Nepal is a pocket area of typhoid endemic city due to cross contamination of food and drinking water with sewage and poor sanitation status. Estimation of the disese burden and its etiology would be helpful in the development of effective prevention and control intervention 5. Out of 200 cultures confired typhoid fever cases, 180 were caused by salmonella typhi and 20 were by Salmonella Para Typhi. Such a higher prevalence of typhi serovars in our study complies with the study by Adhikari et al, (64%) and (35.9%) of Salmonella and Salmonella respectively 6. In accordance to this study such a high prevalence of Salmonella Typhi was due to contaminated drinking water supply ia small Nepali town has recently been described 11. However Shirawa et al documented Salmonella Paratyphi are more prevalent serovar in Kathmandu, Nepal 7. Which is suppported by another study of Pramod et al., (35.9%). Salmonella and (64.1%) Salmonella Paratyphi 8. Although, there is no such well established cause of serovar vriation in tyhphoid cases. Higher incidence of Salmonella Typhi might be due to waterborne transmission of Salmonella Typhi as it usually involves smaller inocula than paratyphoid achieved through food borne transmission that require large inocula 9.

In accordance to this study, more prevalent rate of typhoid cases was in male than females 10. Which was done by Mohantyet al 2006 in All iIndia institute of Medical science. The one of the strong reason for such a high rate in males were that males in Nepal, at present also usually worked outside their homes and also eat street food and drinking water are liable to contaminated.

This study shows the frequency of typhoid fever is higher in male population compared to female population. Likewise, the result of this investigation shows the prevalence organism for causing typhoid fever is Salmonella typhi than Salmonella partyphi A. It might be due to the reason that salmonella typhi requires smaller number to cause the disease. But for causing partyphoid fever, the causative organism i. e. Salmonella paratyphi A requires only the small numbers.