Environmental Awareness and Hygienic Measures Taken Based on a Case Control Study Prevent Further Outbreak of Indian Tick Typhus in and Around Village Deol, Kangra, Himachal Pradesh, India–A Seven Years Follow–Up Study

Rajesh K. Sood; Omesh K. Bharti; Vidya Ramachandran

Volume : V, Issue : II, February - 2015

Environmental Awareness and Hygienic Measures Taken Based on a Case Control Study Prevent Further Outbreak of Indian Tick Typhus in and Around Village Deol, Kangra, Himachal Pradesh, India–A Seven Years Follow–Up Study

Rajesh K. Sood, Omesh K. Bharti, Vidya Ramachandran

Abstract :

T Background: Rickettsial diseases (typhus) is a group of re–emerging infections, which manifests itself as nonspecific feile illness & pose a serious public health problem when not diagnosed or misdiagnosed. Tick borne disease has been reported among international travelers. An outeak of tick borne typhus was reported in Botswana among U.S. Soldiers participating in training exercise in Botswana with high attack rates. In a recent study in south India 7.7 % of pediatric patients with fever of unknown origin had spotted fever. On 9/7/2007 a pediatrician telephonically informed the Chief Medical Officer Kangra regarding high number of fever cases in Deol Village. Fever presenting with excessive perspiration, headache, chills & rigors. The author was asked to confirm & investigate the outeak and suggest protective measures to be taken. Methods: We collected baseline fever data for a period of 5 years. We talked to local people, local service providers to verify if similar disease had occurred in the past & we confirmed that it was an unusual event. We defined a suspected case as occurrence of fever with or without chills or headache with onset from Mid April– Mid August 2007, in a resident of village Deol with no established alternative diagnosis & conducted house to house searches and enumerated the village population. We also collected blood slides for malarial parasite, serum samples for serology for typhus & blood stool samples for salmonella culture. We conducted in depth interviews of key informants regarding the occupation, common activities in the area, obtained data on temperature humidity & rainfall for the last five years to correlate the environmental variables with the outeak. We inspected the water source & collected water samples for examination for coliform bacteria. We examined animals for the presence of ticks & sent tick samples for identification. We then conducted a case control study with all 25 lab confirmed cases & 25 age sex & neighborhood matched controls. We collected information on socio– demographic variables, various suspected exposures using a pre tested structured questionnaire to find out the risk factors and take preventive measures. Results : We found 332 cases (over 17 weeks) from Deol. The incidence of fever in July 2007 was in excess of the expected frequency by more than 2 standard deviations & confirmed to the definition of an outeak. The common clinical features were fever with chills in 86% followed by fever with headache in 83% & Fever with cough 24%: One case showed 2 eschars. The first case was on 15th April the epi–curve peaked in the week ending 7th July & then declined. The attack rate was 26 % & more in females (32%) than in males (20%). The attack rate was highest in age group of 5–14 (38%), followed by 15–29 yrs (29%). Geographic distribution shows that attack rates were highest among areas close to forest. No pathogens were isolated in the 3 Stool cultures or 6 blood cultures. Blood film examination for malaria was negative. According to the lab reports of CRI Kasauli, 12 cases of 19 had a titer of >1:80 on Weil Felix. IgM ELISA done at NCDC, Delhi reported 10 of 16 samples positive for Indian tick typhus R. conorri. 2 cases had a significant rise in titers from 1: 80 to 1:1240. A total of 25 cases had IgM Elisa positive or Weil Felix titer > 1: 80. The comparison of various exposures among case patients & healthy controls showed that those changing clothes weekly or less frequently had 29 times higher risk of getting the disease, whereas for exposure to tall grass in the neighborhoods it was 14 times higher risk. Travel to forest, bathing animals frequently, less than thrice weekly; personal bathing frequency more than weekly, farming & having tick infested animal in the house were associated with a higher risk of getting disease. Having a household contact with fever case was associated with a 4 times higher risk of getting the diseases. Other factors like having a mud house, ownership of animals in family were not significantly associated with risk of illness. The village people go to the forest/ grasslands to collect grass or graze the cattle The in depth interviews of key informants revealed that tick paralysis is common among the sheep in spring when crossing forest to grazing pastures.. Riphicephalus ticks which are associated with Indian tick typhus were physically found on the animals. Conclusions: The high risk associated with poor personal hygiene is corroborated with the life cycle of the tick. The larval stage of the ticks will get washed off the body with good personal hygiene like frequent changing of clothes and bathing. The spurt in rainfall & humidity in beginning of June corresponds to increase in vegetation height & increased propagation of ticks. Recommendation: The people were advised to bathe daily & change clothes frequently. Exposure to forest & farm activity needs alert behaviour and people need to get the animals treated for the tick infestation regularly. We sensitized the local medical officer & a system was put in place for regular surveillance of the disease based on case definition of fever. No cases have been reported in last more than seven years as a system of effective surveillance is in place for detection of any such cases and people are continuously sensitized to maintain hygiene and be vigilant during rainy season and de–tick the animals regularly