National Health Programs (NHP) - Vector Borne Diseases

Overview of the National Vector Borne Disease Control Program (NVBDCP)

The National Vector Borne Disease Control Program ($NVBDCP$) is a specialized initiative implemented across States and Union Territories in India for the prevention and control of six specific vector-borne diseases. These diseases include Malaria, Filariasis, Kala-azar, Japanese Encephalitis ($JE$), Dengue, and Chikungunya. Out of these six diseases, five (Malaria, Filariasis, Japanese Encephalitis, Dengue, and Chikungunya) are transmitted via mosquitoes, while Kala-azar is transmitted by the sandfly. The administrative nodal agency for this program is the Directorate of $NVBDCP$, which operates under the Directorate General of Health Services within the Ministry of Health and Family Welfare of the Government of India.

The overarching strategy of the $NVBDCP$ is multifaceted, focusing on disease management, integrated vector management ($IVM$), and supportive interventions. Disease management includes early case detection ($ACD$ and $PCD$) and complete treatment, the strengthening of referral services, epidemic preparedness, and rapid response. Integrated Vector Management ($IVM$) is prioritized alongside supportive interventions such as Behavior Change Communication ($BCC$), Public-Private Partnerships ($PPP$), intersectoral coordination, and comprehensive human resource management. Furthermore, specific medical interventions are employed including vaccination for Japanese Encephalitis and Mass Drug Administration ($MDA$) for lymphatic filariasis.

Historical Milestones and Evolution of Malaria Programs

The history of malaria control in India is marked by several significant transition points, beginning with the National Malaria Control Program ($NMCP$) in $1953$. This was succeeded by the National Malaria Eradication Program in $1958$. However, the $1970$s saw a resurgence of malaria due to inadequate vector control, improper drug treatment protocols, and mosquito mutations. This led to the introduction of the Urban Malaria Scheme in $1971$ and the Modified Plan of Operations in $1977$. In subsequent years, the program evolved through the Enhanced Malaria Control Project ($EMCP$) in $1997$ and the National Anti-Malaria Program ($NAMP$) in $1999$. By $2003$ to $2004$, the $NVBDCP$ was established, becoming part of the National Rural Health Mission ($NRHM$) in $2005$. Technological advancements were introduced shortly after, including Rapid Diagnostic Tests ($RDT$) in $2005$, Artemisinin-based Combination Therapy ($ACT$) in $2006$, and Long-Lasting Insecticidal Nets ($LLIN$s) in $2009$. Currently, the initiative is guided by the National Framework for Malaria Elimination ($2016$-$2030$) and successive National Strategic Plans for Malaria Elimination spanning from $2017$ to $2027$.

Organizational Structure of the National Health Programs

At the national level, the Directorate of $NVBDCP$ is headed by a Malaria Program Officer ($MPO$). At the state level, there are $19$ Regional Offices located across $19$ states under the Directorate General of Health Services. Every state contains a Vector Borne Disease Control Division headed by a State Program Officer ($SPO$), along with a State Vector Borne Disease Control Society, which is typically merged into a State level Health and Family Welfare Society. At the district level, operations are managed by a District Malaria Officer ($DMO$) or a District Vector Borne Disease Control Officer who assists the $CMHO$ or $DHO$, supported by Assistant Malaria Officers ($AMO$) and Malaria Inspectors ($MI$s). District Vector Borne Disease Control Societies are merged with District Health Societies under the $NRHM$ framework.

Peripheral health services at the Primary Health Centre ($PHC$) level involve a Medical Officer ($MO$) overseeing surveillance, laboratory, and spray services. Multipurpose workers (male) handle active surveillance, while laboratory technicians examine blood smears using one microscope provided per $2000$ population. At the subcentre level, malaria clinics and drug distribution centres are responsible for providing anti-malarial tablets and the impregnation of bed nets. Fever Treatment Depots ($FTD$s) are also established at this level. At the village level, the Accredited Social Health Activist ($ASHA$) distributes tablets, impregnates nets, and collects blood slides. Each village is supposed to have one Fever Treatment Depot with $RDT$ kits and community outreach services. In high Plasmodium falciparum ($Pf$) areas, a link worker is assigned for every $2000$ population to collect smears and provide presumptive treatment.

Urban Malaria Scheme and Operational Plans

The Urban Malaria Scheme, initiated in $1971$, aims to reduce malaria transmission, morbidity, and mortality in cities and towns. It is specifically implemented in urban areas with a population exceeding $50,000$, an Annual Parasite Incidence ($API$) of $\ge 2$, or a Slide Positivity Rate ($SPR$) of $\ge 5\%$. Currently, it covers $131$ towns across $19$ States and Union Territories. Strategies include the implementation of civil by-laws to prevent mosquito breeding in domestic and peridomestic settings, integrated vector management, active surveillance, and the establishment of malaria clinics in mega-cities.

The Modified Plan of Operation, launched in $1977$, marked the shift from eradication to control. Areas were divided based on an $API$ threshold of $2$. In areas where API > 2, insecticidal spraying is conducted at six-week intervals, supported by malaria surveillance, case treatment, decentralization of labs, and the use of Fever Treatment Depots and Drug Distribution Centers. In areas where API < 2, focal spraying of $DDT$, $BHC$, or Malathion is performed in $Pf$-affected areas, complemented by active and passive surveillance, presumptive treatment for suspected cases, radical treatment for confirmed cases, and investigative efforts into causative factors.

National Framework for Malaria Elimination ($2016$ - $2030$)

Launched in $2016$, the National Framework for Malaria Elimination classifies States and UTs into four categories. Category $3$ is the Intensified Control Phase for areas with an $API \ge 1$ case per $1000$ population ($2$ states/UTs). Category $2$ is the Pre-Elimination Phase for areas with an aggregate API < 1 but containing specific districts where API > 1 ($7$ states/UTs). Category $1$ is the Elimination Phase where all districts have an API < 1 ($25$ states/UTs). Category $0$ is the Prevention and Re-establishment Phase for areas with zero indigenous cases ($2$ states/UTs). The primary goals are to achieve zero indigenous cases throughout the country by $2030$ and maintain that status. Key objectives include interrupting transmission in all states by $2027$ and initiating the certification process for malaria-free status by the end of $2030$ after sustaining zero cases for three consecutive years.

Planning is decentralized with the district as the primary unit. States categorize their districts, and districts may sub-categorize blocks into different phases based on their specific $API$. This allows blocks in Category $2$ districts that have low incidence to initiate elimination phase activities. This hierarchy extends down to the Primary Health Centre, Subcentre, and village levels. Strategies for high-incidence Category $3$ areas involve screening all fever cases, risk grading, and establishing mobile clinics in tribal or conflict-affected regions. Category $1$ areas focus on setting up elimination surveillance systems, investigating and classifying all malaria foci, and screening household members, neighbors, and colleagues of positive cases. A national level reference laboratory is utilized to double-check $100\%$ of cases after elimination and to certify microscopists.

Specialized Malaria Interventions and Global Collaboration

The Tribal Malaria Action Plan initially covers Categories $3$ and $2$ and utilizes hamlet-wise $ASHA$s. In areas without an $ASHA$, local providers, village heads, teachers, or forest workers are trained. Mobile health services are used in areas with civic disturbances. The Enhanced Malaria Control Project ($EMCP$) is a World Bank-supported initiative targeting tribal populations in Primary Health Centres where the tribal population is at least $25\%$, the $API$ has been > 2 for the last three years, $Pf$ cases exceed $30\%$, or malaria deaths have recently occurred. Additionally, June is designated as Anti-Malaria Month to enhance awareness before the monsoon transmission season.

Malaria control is integrated with other programs such as the Integrated Disease Surveillance Program ($IDSP$) for weekly fever alerts, the Reproductive and Child Health ($RCH$) and Janani Suraksha Yojana ($JSY$) for distributing $LLIN$s to pregnant women, and the Integrated Management of Neonatal and Childhood Illness ($IMNCI$) for case management. The High Burden High Impact ($HBHI$) initiative, launched by the $WHO$, focuses on intensifing elimination in West Bengal, Jharkhand, Chhattisgarh, and Madhya Pradesh. The Global Fund to fight AIDS, TB, and Malaria ($GFATM$) has supported India since $2005$, currently funding the Intensified Malaria Elimination Project $2$ in Odisha, Jharkhand, Chhattisgarh, and seven North Eastern States (Arunachal Pradesh, Assam, Meghalaya, Mizoram, Nagaland, Manipur, and Tripura).

Elimination of Lymphatic Filariasis ($ELF$)

The National Filariasis Control Program ($NFCP$) began in $1955$ and was extended to rural populations in $1994$ before becoming part of the $NVBDCP$ in $2003$. Elimination is defined as the point where lymphatic filariasis ceases to be a public health problem, specifically when the number of microfilaria carriers is less than $1\%$ and children born after the initiation of the program are free from circulating Antigenaemia. The main strategy is the annual Mass Drug Administration ($MDA$) starting in November. This involves door-to-door drug administration for five or more years using combinations like $DA$ (Diethylcarbamazine or $DEC$ plus Albendazole) or $IDA$ (Ivermectin plus $DEC$ plus Albendazole). Achieving $80\%$ coverage for $5$ to $6$ years can interrupt transmission, as the fertility of the adult parasite is approximately $4$ to $6$ years.

Supportive management includes home-based care for lymphoedema cases and upscaling hydrocele operations. Surveys play a critical role, including night blood surveys for microfilaria in sentinel sites and Transmission Assessment Surveys ($TAS$). $TAS$ is conducted six months after the fifth round of $MDA$ provided there was $65\%$ coverage and a microfilaria rate of < 1\%. New monitoring tools include the SukRtya app in Bihar and the $CS$ Pro app in Uttar Pradesh. Achievements to date include $98$ districts clearing the first $TAS$, $88$ districts clearing the second, and $42$ districts clearing the third.

National Kala-azar Elimination Program

Launched as a centrally sponsored program in $1990$-$91$, the National Kala-azar Elimination Program aims to reduce the annual incidence of the disease to less than $1$ per $10000$ population at the block $PHC$ level. Objectives include reducing case fatality and preventing co-infections with $HIV$ or Tuberculosis. Strategies involve enhanced case detection using rapid diagnostic kits and treatment with medications such as Liposomal Amphotericin B ($LAMB$), Miltefosine, Amphotericin B Deoxycholate, or Paromomycin. Vector control is achieved through Indoor Residual Spraying ($IRS$) using $50\%$ $DDT$, or synthetic pyrethroids in areas with $DDT$ resistance.

Incentives are provided to encourage participation and support. An $ASHA$ worker receives $\text{Rs. } 300$ for identifying a case and $\text{Rs. } 100$ for ensuring one round of spraying (or $\text{Rs. } 200$ for two rounds). Patients receive $\text{Rs. } 500$ for Kala-azar treatment as wage compensation and $\text{Rs. } 2000$ for Post-Kala-azar Dermal Leishmaniasis ($PKDL$) treatment. Currently, Uttar Pradesh, Bihar, Jharkhand, and West Bengal have achieved elimination targets at the block level, with all endemic blocks reporting incidences below the threshold of $1$ case per $10000$ population.

Programs for Japanese Encephalitis, Dengue, and Chikungunya

The National Program for Control and Prevention of Japanese Encephalitis ($JE$) focuses on strengthening vaccination, surveillance, and vector control. $JE$ vaccination using the live attenuated $SA-14-14-2$ vaccine began in $2006$ and was included in the Routine Immunization ($RI$) schedule in $2013$. Surveillance types include epidemiological, entomological, and veterinary-based monitoring. Health education efforts emphasize keeping pigs away from human dwellings and encouraging early reporting of signs and symptoms.

For Dengue and Chikungunya, the program utilizes a network of $521$ Sentinel Surveillance Hospitals and $14$ Apex Referral Laboratories. The National Institute of Virology in Pune provides $IgM$ capture $ELISA$ test kits for diagnosis after the fifth day of infection, while $NS1$ kits are used for early detection from the first day. Dengue has been a notifiable disease since $2016$. Strategies for both diseases are identical because they share the same vector. Outbreak response includes fever alert surveillance where workers report directly to the District $VBDC$ officer, supplemented by $IDSP$ reporting. Currently, efforts have resulted in an $84\%$ reduction in malaria morbidity and a $76\%$ reduction in mortality nationwide, with zero malaria cases in $116$ districts and an API < 1 in $34$ States and UTs, with exceptions in Tripura and Mizoram.