|
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.
|
Introduction
Dengue
fever is one of the oldest arthropod- borne viral diseases known in India. Outbreaks of dengue
fever/dengue haemorrhagic fever (DF/DHF) have been
reported from various parts of the country(1,2,3).
Rapid transportation, industria-lization, movement
of infected human populations/mosquitoes and the changing ecology have
facilitated its spread to newer areas (4,5,6).
During 1991-1995, a total of 18 DF/DHF outbreaks were reported from different
parts of the country, and the trend shows that the disease is occurring with
increased frequency (7). A widespread outbreak of DF/DHF occurred
in Delhi and its surrounding areas during
1996(8).Similar outbreaks were also reported from the neighbouring state of Haryana(8).
In October 1996, a suspected dengue/DHF outbreak was reported from Ludhiana city of Punjab state. Following the outbreak, a
team of specialists from the National Institute of Communicable Diseases
(NICD), Delhi, investigated the outbreak and the findings of its
investigations are presented in this paper.
Area
Ludhiana is a fast growing city of Punjab situated about 300 km away from Delhi in the north-west. It has a
sizeable migratory popu-lation. It has 66
municipality wards. The city is roughly divided into new and old parts by a
big drain/nullah. Old city is a highly
congested area. The city has one civil hospital and a number of private
hospitals.
Anti-mosquito measures
In
Ludhiana, a city corporation is respon-sible for all the anti-mosquito activities. The
district malaria office is also involved in anti-larval measures by using Malariol and Fenthion. Generally,
these measures are directed towards the control of clux
quinquefasciatus.
Methodology
The
methodology used in this investigation included collection of institutional
data regarding line-listing of cases and clinical details. Blood samples were
collected from acute and convalescent cases admitted in different hospitals
for laboratory confirma-tion of the aetiology. Rapid fever survey and entomological
collections were carried out in the localities from where suspected
dengue/DHF cases or deaths had been reported.
Results and discussions
Epidemiological
a) Hospital records :
Cases of dengue/ DHF, based on clinical and laboratory criteria like high
fever, headache, body-ache, rash, bleeding manifestations and low platelet
count, were admitted in two major hospitals, viz. Dayanand
Medical College (DMC) Hospital and the Christian Medical College (CMC)
Hospital. The first case was admitted in DMC hospital on 24 September.
Up to 18 October, a total of 67 cases were treated in the two hospitals.
The proportion of cases by age was 0-10 years (22.4%), 11-20 years (32.8%),
21-30 years (16.4%) and > 31 years (26.9%). Both sexes were almost
equally affected and cases were mostly among young adults and children, the
youngest being seven-and-a-half-years old. The sympto-matology
of admitted cases included fever (100%), headache, body-ache, petechiae (8%), frank haemorrhagic
manifestations (5%), rash (3%) and very low platelet
count (100%).
b) Community survey :
Among the 2897 persons surveyed for the occurrence of fever cases, with one
week recall period in the community, 119 fever cases were detected (attack
rate 4.10%). The age-wise analysis of the cases showed that proportions
included in the age group were 0-10 years (21%), 11-20 years (28.6%), 21-30
years (21%) and >31 years (29.4%). Both sexes suffered almost equally. The
area-wise attack rate of fever cases from the community showed that Shivaji Nagar area was the
worst affected, with an attack rate of 7.9%, Fatehgarh
with 1.7%, Khud Mohalla
with 1.3% and Indrapuri with 0.6%.
The
outbreak started in the last week of September 1996 and lasted up to the
first week of December 1996 during which period a total of 720 cases (deaths
19) were reported (Figure 1) (Source: Directorate of Health Services,
Punjab). The maximum number of cases were reported
during the third week of November 1996.
Serological
Nine
serum samples collected from acute and convalescent patients were tested by Haemagglutination Inhibition Test(9), using
antigen and antisera received from Centers for
Disease Control, USA, and dengue IgM immunoblot commercial kit (Gene Labs, Singapore ). Seven
of these sera were found to be positive for diagnostic dengue antibodies by HI(10) and/or IgM
immunoblot test. One sample showed low level of
antibodies to dengue.
Entomological
The
areas surveyed for Aedesmosquito
breeding places were Civil Lines, Civil Surgeon’s Office complex, DayaNandMedicalCollege and Hospital area, Durga Puri colony and Shivaji Nagar colony. In these
areas, Aedes survey was carried out in and
around those houses from where suspected dengue fever/DHF cases or deaths had
been reported. Houses were searched for Aedes
mosquito’s larvae in various water collections/containers as per single larva
technique and the results are summarized in the table below.
Table. Aedes aegypti indices in different localities of Ludhiana
|
Sr.No.
|
Locality
|
House Index
|
Container Index
|
|
1.
|
Civil Surgeon’s office complex
|
44.4
|
33.3
|
|
2.
|
Civil Lines residential flats
|
26.3
|
18.5
|
|
3.
|
DayaNandMedicalCollege & Hospital
|
83.3
|
52.0
|
|
4.
|
Durga Puri
colony
|
27.7
|
21.7
|
|
5.
|
Shivaji Nagar
colony
|
23.8
|
23.5
|
During
the survey a total of 73 houses/ premises were searched for Aedes breeding and 24 were found positive (House
Index 32.8 %). Similarly, a total of 120 containers were searched and 35 were
found positive (Container Index 29.16%). These indices were found to be
higher than the critical index reported for dengue/DHF outbreaks(11).
The
bulk of Aedesbreeding sites com-prised of desert-coolers. Other containers found positive
for Aedesbreeding were tin/plastic
containers, flower vases, earthen pots, plastic buckets, etc. Adults of Aedes aegypti were
also collected from inside rooms and water receptacles, particularly inside
earthen pots and desert coolers. The entomological investigation revealed a
significantly higher House Index and Container Index for Aedes
aegypti mosquito, a proven vector of DF/ DHF.
The presence of this vector mosquito in Punjab state has already been documented(12). However, higher
larval indices of Aedes aegypti were found during the present investigation,
thus indicating that the species is well established in Ludhiana city.
Conclusion
The
clinical, epidemiological, laboratory and entomological findings of the
investigation indicate that the present outbreak in Ludhiana was of DF/DHF. The prevalence of
DF/DHF in Ludhiana has been reported for the first
time in Punjab state. The last epidemic of
dengue outbreak, reported from the northern part of the country, was from Jammu in the year 1974(14).
The current outbreak showed that the disease was now taking root in the
plains of Punjab. The occurrence of dengue/DHF
outbreak in Ludhiana emphasizes the urgent need for
taking appropriate preventive measures and for surveillance of the
disease/vector in order to prevent further such outbreaks in other parts of
the state and in the region.
Acknowledgement
The
authors are grateful to Dr K.K. Datta, former Director, NICD, for technical
guidance. They are thankful to the Civil Surgeon and District Malaria Officer
of Ludhiana district for their help and
cooperation during the field investigation and data collection. Thanks are
also due to Mr Ravi Kumar, Research Assistant, and Mr N. A. Khan, Technician,
for their technical assistance.
References
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 India.
Def. Sci. J, 1982, Vol.32 (4): 359-370.
3. Gupta
NP. Arboviruses in India- Part-II. ICMR Bulletin,
1980, 10 (5) 57-66.
4. World
Health Organization. Monograph on dengue/dengue haemorrhagic
fever. Regional Publication, SEARO No.22, 1993.
5. Banerjee K. Emerging viral infections with special
reference to India.
Indian J. Med. Res. 1996, 103, 177-200.
6. Handbook
of infectious diseases titled "Exotic viral infection". Edited by J.S.Porterfield. Chapman and Hall, London,
1995, 103-146.
7. Bandyopadhyay S, Jain DC
and Datta KK. Reported incidence of dengue/dengue haemorrhagic
fever in India
1991-1995. WHO/SEARO Dengue Bulletin 1996, 20:33-34.
8. World
Health Organization. Management of dengue epidemics – A report of the
technical meeting, SEARO, New Delhi,
1997, SEA/DEN/VBC/55.
9. Clarke
DH and Casals J. Techniques of haemagglutination
and haemagglutination inhibition with
arthropod-borne viruses. Am. J. - Trop. Med. Hyg.
1958, 7: 561-573.
10. Anonymous.
Dengue haemorrhagic fever – Diagnosis, treatment
and control. World Health Organization, Geneva,
1986, 27-28.
11. Rahman SJ, Jalees Saba, Sharma
RS and Verghese T. Relevance of Aedes
larval /house index in predicting outbreaks of dengue/ dengue haemorrhagic fever. Dengue Newsletter 1992, 17:
pp.5-7.
12. Kalra NL, Wattal BL and Raghavan NGS. Distribution pattern of Aedes
( Stegomyia) aegypti in India
- Some ecological considerations. Bull.Ind.
Soc. Mal. Com. Dis. 1968, 5: 307-334.
13. Mathew
T, Suri JC, Suri NK, Bhola SR, Arora RR, Lal P, Raichaudhari
AN, Mathur KK and Gupta JP. Investigation of an
epidemic of dengue in Jammu,
1974. Indian J.Med.Res. 1977, 65:613-622
|
