Dengue Outbreak in Ludhiana (Punjab), India, 1996

By Kuldip Singh Gill, D. Bora, M. Bhardwaj, S. Bandyopadhyay, Kaushal Kumar and Rakesh Katyal National Institute of Communicable Diseases 22 Sham Nath Marg, Delhi-110054.

Abstract

An outbreak of dengue fever/dengue haemorrhagic fever was reported from Ludhiana city in Punjab state, India, during October 1996. The outbreak started in the last week of September and lasted up to the first week of December. The number of cases reported during the outbreak was 720, with 19 deaths. A community survey revealed a very high attack rate of fever cases (4.10%). Serological tests suggested a recent dengue virus infection as seven serum samples out of nine tested were found to be positive. Aedes survey carried out in some of the affected localities revealed the presence of Aedes aegypti, a vector mosquito. The values of House and Container indices in Ludhiana city during the survey were 32.8% and 29.16% respectively. Breeding of Aedes mosquitoes was detected in various types of containers, mostly desert- coolers. To prevent such outbreaks in the state of Punjab and in the region, there is an urgent need for taking appropriate preventive measures and for disease/vector surveillance.

(7) Introduction occurring with increased frequency . A widespread outbreak of DF/DHF occurred Dengue fever is one of the oldest in Delhi and its surrounding areas during (8) arthropod- borne viral diseases known in 1996 . Similar outbreaks were also India. Outbreaks of dengue fever/dengue reported from the neighbouring state of (8) haemorrhagic fever (DF/DHF) have been Haryana . In October 1996, a suspected reported from various parts of the dengue/DHF outbreak was reported from country(1,2,3). Rapid transportation, industria- Ludhiana city of Punjab state. Following lization, movement of infected human the outbreak, a team of specialists from populations/mosquitoes and the changing the National Institute of Communicable ecology have facilitated its spread to Diseases (NICD), Delhi, investigated the newer areas (4,5,6). During 1991-1995, a outbreak and the findings of its total of 18 DF/DHF outbreaks were investigations are presented in this paper. reported from different parts of the country, and the trend shows that the disease is

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Dengue Outbreak in Ludhiana (Punjab), India, 1996

ache, rash, bleeding manifestations and Area low platelet count, were admitted in two Ludhiana is a fast growing city of Punjab major hospitals, viz. Dayanand Medical situated about 300 km away from Delhi in College (DMC) Hospital and the Christian the north-west. It has a sizeable migratory Medical College (CMC) Hospital. The first popu-lation. It has 66 municipality wards. case was admitted in DMC hospital on The city is roughly divided into new and 24 September. Up to 18 October, a total of old parts by a big drain/nullah. Old city is a 67 cases were treated in the two highly congested area. The city has one hospitals. The proportion of cases by age civil hospital and a number of private was 0-10 years (22.4%), 11-20 years hospitals. (32.8%), 21-30 years (16.4%) and > 31 years (26.9%). Both sexes were almost equally affected and cases were mostly Anti-mosquito measures among young adults and children, the In Ludhiana, a city corporation is respon- youngest being seven-and-a-half-years sible for all the anti-mosquito activities. old. The sympto-matology of admitted The district malaria office is also involved cases included fever (100%), headache, in anti-larval measures by using Malariol body-ache, petechiae (8%), frank and Fenthion. Generally, these measures haemorrhagic manifestations (5%), rash are directed towards the control of clux (3%) and very low platelet count (100%). quinquefasciatus. (b) Community survey : Among the 2897 persons surveyed for the occurrence of Methodology fever cases, with one week recall period in the community, 119 fever cases were The methodology used in this investigation detected (attack rate 4.10%). The age- included collection of institutional data wise analysis of the cases showed that regarding line-listing of cases and clinical proportions included in the age group details. Blood samples were collected from were 0-10 years (21%), 11-20 years acute and convalescent cases admitted in (28.6%), 21-30 years (21%) and >31 different hospitals for laboratory confirma- years (29.4%). Both sexes suffered almost tion of the aetiology. Rapid fever survey and entomological collections were carried equally. The area-wise attack rate of fever out in the localities from where suspected cases from the community showed that dengue/DHF cases or deaths had been Shivaji Nagar area was the worst affected, reported. with an attack rate of 7.9%, Fatehgarh with 1.7%, Khud Mohalla with 1.3% and Indrapuri with 0.6%. Results and discussions The outbreak started in the last week of Epidemiological September 1996 and lasted up to the first week of December 1996 during which (a) Hospital records : Cases of dengue/ period a total of 720 cases (deaths 19) DHF, based on clinical and laboratory were reported (Figure 1) (Source: criteria like high fever, headache, body- Directorate of Health Services, Punjab). The

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Dengue Outbreak in Ludhiana (Punjab), India, 1996

Figure 1. Week-wise distribution of dengue/DHF cases, Ludhiana, 1996

maximum number of cases were reported these areas, Aedes survey was carried during the third week of November 1996. out in and around those houses from where suspected dengue fever/DHF cases or deaths had been reported. Serological Houses were searched for Aedes Nine serum samples collected from acute mosquito’s larvae in various water and convalescent patients were tested by collections/containers as per single larva Haemagglutination Inhibition Test(9), using technique and the results are summarized antigen and antisera received from in the table below. Centers for Disease Control, USA, and Table. Aedes aegypti indices in different dengue IgM immunoblot commercial kit localities of Ludhiana (Gene Labs, Singapore ). Seven of these Sr. House Container sera were found to be positive for Locality No. Index Index diagnostic dengue antibodies by HI(10) Civil Surgeon’s 1. 44.4 33.3 and/or IgM immunoblot test. One sample office complex showed low level of antibodies to dengue. Civil Lines 2. 26.3 18.5 residential flats Daya Nand Entomological 3. Medical College & 83.3 52.0 Hospital The areas surveyed for Aedes mosquito 4. Durga Puri colony 27.7 21.7 breeding places were Civil Lines, Civil Shivaji Nagar 5. 23.8 23.5 Surgeon’s Office complex, Daya Nand colony Medical College and Hospital area, Durga Puri colony and Shivaji Nagar colony. In

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Dengue Outbreak in Ludhiana (Punjab), India, 1996

During the survey a total of 73 houses/ showed that the disease was now taking premises were searched for Aedes root in the plains of Punjab. The breeding and 24 were found positive occurrence of dengue/DHF outbreak in (House Index 32.8 %). Similarly, a total of Ludhiana emphasizes the urgent need for 120 containers were searched and 35 taking appropriate preventive measures were found positive (Container Index and for surveillance of the disease/vector 29.16%). These indices were found to be in order to prevent further such outbreaks higher than the critical index reported for in other parts of the state and in the dengue/DHF outbreaks(11). region.

The bulk of Aedes breeding sites com- prised of desert-coolers. Other containers Acknowledgement found positive for Aedes breeding were tin/plastic containers, flower vases, The authors are grateful to Dr K.K. Datta, earthen pots, plastic buckets, etc. Adults former Director, NICD, for technical of Aedes aegypti were also collected from guidance. They are thankful to the Civil inside rooms and water receptacles, Surgeon and District Malaria Officer of particularly inside earthen pots and desert Ludhiana district for their help and coolers. The entomological investigation cooperation during the field investigation revealed a significantly higher House and data collection. Thanks are also due Index and Container Index for Aedes to Mr Ravi Kumar, Research Assistant, aegypti mosquito, a proven vector of DF/ and Mr N. A. Khan, Technician, for their DHF. The presence of this vector technical assistance. mosquito in Punjab state has already been documented(12). However, higher larval indices of Aedes aegypti were found during the present investigation, thus References indicating that the species is well established in Ludhiana city. 1. Yadav RL and Narasimham MVVL. Dengue/ dengue haemorrhagic fever and its control in India. Dengue Newsletter, 1992, Vol 17: 3-8.

2. Pandya G. Prevalence of dengue infection in Conclusion India. Def. Sci. J, 1982, Vol.32 (4): 359-370. The clinical, epidemiological, laboratory 3. Gupta NP. Arboviruses in India- Part-II. ICMR and entomological findings of the Bulletin, 1980, 10 (5) 57-66. investigation indicate that the present outbreak in Ludhiana was of DF/DHF. The 4. World Health Organization. Monograph on dengue/dengue haemorrhagic fever. Regional prevalence of DF/DHF in Ludhiana has Publication, SEARO No.22, 1993. been reported for the first time in Punjab state. The last epidemic of dengue 5. Banerjee K. Emerging viral infections with outbreak, reported from the northern part special reference to India. Indian J. Med. Res. 1996, 103, 177-200. of the country, was from Jammu in the year 1974(14). The current outbreak

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6. Handbook of infectious diseases titled “Exotic 11. Rahman SJ, Jalees Saba, Sharma RS and viral infection”. Edited by J.S.Porterfield. Verghese T. Relevance of Aedes larval /house Chapman and Hall, London, 1995, 103-146. index in predicting outbreaks of dengue/ dengue haemorrhagic fever. Dengue Newsletter 1992, 7. Bandyopadhyay S, Jain DC and Datta KK. 17: pp.5-7. Reported incidence of dengue/dengue haemorrhagic fever in India 1991-1995. 12. Kalra NL, Wattal BL and Raghavan NGS. WHO/SEARO Dengue Bulletin 1996, 20:33-34. Distribution pattern of Aedes ( Stegomyia) aegypti in India - Some ecological 8. World Health Organization. Management of considerations. Bull.Ind. Soc. Mal. Com. Dis. dengue epidemics – A report of the technical 1968, 5: 307-334. meeting, SEARO, New Delhi, 1997, SEA/DEN/VBC/55. 13. Mathew T, Suri JC, Suri NK, Bhola SR, Arora RR, Lal P, Raichaudhari AN, Mathur KK and 9. Clarke DH and Casals J. Techniques of Gupta JP. Investigation of an epidemic of haemagglutination and haemagglutination dengue in Jammu, 1974. Indian J.Med.Res. inhibition with arthropod-borne viruses. Am. J. - 1977, 65:613-622 Trop. Med. Hyg. 1958, 7: 561-573.

10. Anonymous. Dengue haemorrhagic fever – Diagnosis, treatment and control. World Health Organization, Geneva, 1986, 27-28.

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