The Christian Medical College and H

The Christian Medical College and Hospital (CMCH) is a referral hospital with a well established referral microbiology laboratory. There is a good system of documentation of all laboratory records in the Department of Microbiology. Our study has shown that there is a seasonality in V.cholerae and also that there is a significant association between rainfall and V.cholerae over these years. However, this association was not significant in the later part of the study period, that is, from 2005 to 2010. This may be due to the power of the study, insufficient time period, due to changes in the drainage system, availability of good quality drinking water by the government or due to the evolution of the bottled water industry since 2004.

Our survey on bottled water companies revealed that there were 10 companies producing 166,000 litters of water prior to year 2004, while this was 532,000 litters from 2004 to 2010. There were 20 new companies established from 2004 to 2010. The mean consumption of good quality water consumed by an individual prior to 2004 was 0.39 litters, while this was 1.05 litters from 2004 to 2010. Thus, there was a three times increase in good quality water production and consumption in the latter period (2004–2010) which maybe strongly associated with the decline in the incidence of cholera during the second period.

Faruque et al. (2005) and Islam et al. (2004) have reported that cholera epidemics are usually attributed to a single bacterial clone and the outbreak begins from a point source and then spreads. 17 and 18 Several studies have shown cholera epidemics are associated with environmental factors. 5, 6, 7, 9, 19, 20, 21, 22, 23, 24 and 25 However, they have also raised concerns as to what point source cholera spreads from and where the first clone of an epidemic appears. In our study there has been a significant reduction in the number of cases reported during the period 2005–2010. This could be attributed to availability and affordability of good quality of drinking water and also due to improved sewage drainage system established in recent years. Therefore, it is presumed that these changes would have cleared the reservoir of the V.cholerae O1 and O139 types in the city.

Sack et al. (2006) have reported seasonality of V.cholerae. 26 The seasonality was observed during spring peak (during monsoon) and also in the fall peak (after monsoon). They have also reported that the study area Bakerganj can be considered to be an area where V.cholerae O139 is endemic. In our study also we observed seasonality during the months of June and July, whenever we have the south west monsoon. Usually during this period the rainfall is scanty, however higher number of cases were reported. But cases of V.cholerae O1 were reported less during the main monsoon period in the state of Tamil Nadu which falls during the months of November and December. Our data showed that whenever there was a spell of rain then the reporting of cholera cases was less. Similar findings have been reported in other studies. 27

The association between rainfall and humidity and the increase in V.cholerae counts have been shown to be significant by many authors (Rajendran et al., 2011; Lipp et al., 2002; Pascual et al., 2002; Ruiz-Moreno et al., 2007). 2, 28, 29 and 30 Moreover, unlike Bangladesh, Vellore is situated away from the coastal area and therefore the association between V.cholerae and planktonic copepods is ruled out.

The findings of this study are based on hospital surveillance data, consequently there is likely to be under reporting, as a good number of cases of cholera may have been treated by private practitioners. However, there are 7 other hospitals that are catering to the need of the local population in Vellore taluk. As these hospitals have diagnostic facility and are able to treat, may be that the numbers would have come down. However, only two hospitals were established after 2004. Therefore, more infrastructure facilities would not have contributed very much to the reduction in the number of cases. Moreover, the CMCH laboratory has not changed any practices and clinicians still send samples to the laboratory as they had been doing in the past for all watery and loose stool samples even after working hours as emergency samples. Smaller hospitals or clinics generally do not confirm cholera cases based on laboratory confirmation but presumption from a clinical picture. Some hospitals can do just a “hanging drop” and base their diagnosis on this. There are very few labs that have culture and antiserum facilities available.

Thus the 15 years data on V.cholerae would be able to provide a comprehensive knowledge about the epidemiology of V.cholerae in and around Vellore District.

Ethical clearance
This study was approved by the Institutional Review Board of Christian Medical College Vellore; IRB.Min.No.7109 dated 10.03.2010.

Conflicts of interest
All authors have none to declare.

Acknowledgment
We gratefully acknowledge the funding support of CMC Fluid Research grant.

ผลลัพธ์ (ไทย) 3:

วิทยาลัยแพทย์และโรงพยาบาลคริสเตียน ( cmch ) เป็นโรงพยาบาลที่มีการก่อตั้งห้องปฏิบัติการจุลชีววิทยา . มันเป็นระบบดี เอกสารบันทึกปฏิบัติการทั้งหมดในภาควิชาจุลชีววิทยา การศึกษาของเราได้แสดงให้เห็นว่ามีฤดูกาลใน v.cholerae และยังว่ามีความสัมพันธ์ระหว่างปริมาณน้ำฝนและ v.cholerae ผ่านปีเหล่านี้อย่างไรก็ตาม สมาคมนี้อย่างมีนัยสำคัญในส่วนหลังของระยะเวลาที่ศึกษาคือ ตั้งแต่ปี 2548 ถึง 2553 นี้อาจเป็นเพราะพลังของการศึกษาในระยะเวลาไม่เพียงพอเนื่องจากการเปลี่ยนแปลงในระบบการระบายน้ำ พร้อมน้ำดื่มที่มีคุณภาพที่ดี โดยรัฐบาล หรือเนื่องจากการวิวัฒนาการของอุตสาหกรรมน้ำดื่มบรรจุขวด

ตั้งแต่ปี 2004การสำรวจของเราใน บริษัท น้ำดื่มบรรจุขวด พบว่า มี 10 บริษัทผลิต 166 , 000 ซากของน้ำก่อนปี 2004 ขณะนี้ 532000 ซากจาก 2004 ไปยัง 2010 มี 20 บริษัทใหม่ที่ก่อตั้งขึ้นจาก 2004 ไปยัง 2010 ค่าเฉลี่ยการบริโภคที่ดี คุณภาพน้ำบริโภคโดยบุคคลก่อนที่จะ 2004 เป็น 0.39 ลูกหนู ขณะนี้ 1.05 ซากจาก 2004 ไปยัง 2010 ดังนั้น