New Delhi: The weekly count of dengue cases in the capital has started to rise, with about 40 to 50 cases reported in the last two weeks against a previous level of 5 to 15 per week. Despite the disease being declared a “notifiable disease” under the Epidemic Diseases Act, most dengue cases remain “untraceable.”
According to the latest report on vector-borne diseases issued by the Malaria Operations Headquarters of the Municipal Corporation of Delhi (MCD) on 12th September 2022, the city has so far witnessed 295 cases of dengue, of which 156 cases, about 52.8%. — are classified as “untraceable after investigation”, which means that you cannot locate the address or location from which the case arose.
A senior municipal public health department official said the problem of “untraceable cases” acts as an obstacle in the fight against the mosquito-borne disease, defeating the purpose of the order issued by the Delhi government to declare the disease. as a “notifiable disease” in the city.
On October 14, 2021, the Delhi government made dengue fever a notifiable disease under the Epidemic Diseases Act, forcing all hospitals and healthcare institutions to report any cases they receive to the government.
As per Delhi Vector-Borne Diseases Prevention and Control Regulations, 2021, data provided by hospitals will be used to map regions where diseases are spreading and declare it an “infected” or “threatened” area for measures. mosquito control specific.
Dengue surveillance in the city
Although the notification improved the number of cases reported by the various health care institutes, tracking these cases remains problematic. A senior MCD official explained that the municipal agency was previously using a sentinel surveillance system in which 36 major hospitals used to share data on dengue, malaria and chikungunya cases on a weekly basis with the malaria operations headquarters. “This count has gone up more than 5 times. Now more than 180 hospitals and clinics are sharing data on the disease on the portal managed by the department of health services,” the official explained. However, the data remains flawed and a large proportion of cases do not have a specific address or contact number for the patient.
In most cases, the addresses are untraceable. “For example, if the data says Ram Singh from Burari but doesn’t provide contact details or specific address, our field workers can’t carry out concentrated anti-mosquito activities such as fogging, larvicide spraying or IEC awareness activities in the area.” affected”. “explained another official from the anti-malaria headquarters.
Untraceability: long-standing problem
The problem of untraceable dengue cases is not new and so far Delhi has been unable to address this flaw in its mosquito-borne disease control strategy. Similar and poor traceability rates of dengue cases have been observed in the last 5 years. Last year, Delhi recorded 9,613 dengue cases and 23 deaths, making it the second worst annual outbreak on record. Municipal records show that about 1/3 of these cases (2,971 of 9,613) were marked as untracked.
In 2020, 15.57% (167 of 1,072 cases) of reported dengue cases were untraceable, while 47.34% of dengue cases (964 of 2,036) were marked as untraceable in 2019. The lack of supporting data makes it difficult for field staff to carry out mosquito control activities in vulnerable hotspots where a cluster of dengue cases may be emerging.
The civic official says reminders have been sent to hospitals, the health services department and the national vector-borne disease control program to flag the problem. “Hospitals have been requested to report confirmed cases within 24 hours along with accurate information such as patient details, residential address and contact number. The Delhi government health department is also starting a new portal to collect the data related to the disease and we hope that it will help in the gradual decrease of untracked cases”, added an official.
Vulnerable period: Case surge begins in Delhi
Delhi reported an increase in the number of dengue cases in the week ending September 10, 2022, when 51 cases were reported. The city had reported 39 dengue cases in the previous weekly cycle ending September 4, 2022. Last month, the number of cases per week ranged from 5 to 16 dengue cases. Delhi had recorded 16 cases in the weekly cycle ending Aug. 27; and 11, 4 and 5 cases of dengue in the previous three weeks.
September and October are considered the most vulnerable months for dengue cases in the city, an official explained. Five-year data on mosquito breeding detection shows that the weekly mosquito larvae detection count peaked between week 32 and week 38 of the year, with September witnessing peak detection. The peak distribution of cases of mosquito-borne diseases in 2016 was around week 35, in 2017 it was between week 32 and 33; in 2018 it was week 35; in 2019 it was between week 35 and 36, while it peaked between week 37 and 38 in 2020, public health department analysis shows.
Distribution of mosquito breeding sites
In addition to monitoring dengue cases, the public health department is also tasked with controlling mosquito breeding sites and destroying mosquito larvae. Home breeding checkers have detected 1,05,976 positive mosquito breeding sites this year, of which 8,994 sites have been detected in the last week alone. Analysis of mosquito breeding data shows that peridomiciliary containers, such as vases, flower pots, bird pots, cans, tires, water fountains, account for the largest share of mosquito breeding sites (38%). Household water storage containers (drums, buckets, jerrycans, etc.) that are commonly used in water-scarce regions account for the second highest proportion of sites (33%). Desert coolers, which find significant use in Delhi’s arid climate during summers, and elevated tanks rank third and fourth, respectively.
The contribution of each category continues to vary throughout the year. While household water storage containers and desert coolers contribute the most in the summer, peridomestic containers take a larger share in the ongoing monsoon season, according to the corporation’s analysis report. A senior public health official advised that people should not allow water to stagnate in their environment and clean indoor water containers regularly.