H1N1 Cases Research Articles

Spatio-temporal dynamics and drivers of highly pathogenic avian influenza H5N1 in Chile.

Highly pathogenic avian influenza A H5N1 clade 2.3.4.4b (hereafter H5N1) is causing vast impacts on biodiversity and poultry around the globe. In Chile, lethal H5N1 cases have been reported in a wide range of wild bird species, marine mammals, backyard and industrial poultry, and humans. This study describes the spatio-temporal patterns of the current epizootic of H5N1 in Chile and test drivers that could be associated with outbreak occurrence. We used H5N1 cases reported by the Chilean National Animal Health Authority from 5 December 2022 to 5 April 2023. These included wild bird cases confirmed through an avian influenza-specific real-time reverse transcription PCR assay (RT-qPCR), obtained from passive and active surveillance. Data were analyzed to detect the presence of H5N1 clusters under space-time permutation probability modeling, the association of H5N1 with distance and days since the first outbreak through linear regression, and the correlation of H5N1 presence with a number of ecological and anthropogenic variables using general linear modeling. From 445 H5N1 identified outbreaks involving 613 individual cases in wild birds, a consistent wave-like spread of H5N1 from north to south was identified, which may help predict hotspots of outbreak risk. For instance, seven statistically significant clusters were identified in central and northern Chile, where poultry production and wildlife mortality are concentrated. The presence of outbreaks was correlated with landscape-scale variables, notably temperature range, bird richness, and human footprint. In less than a year, H5N1 has been associated with the unusual mortality of >100,000 individuals of wild animals in Chile, mainly coastal birds and marine mammals. It is urgent that scientists, the poultry sector, local communities, and national health authorities co-design and implement science-based measures from a One Health perspective to avoid further H5N1 spillover from wildlife to domestic animals and humans, including rapid removal and proper disposal of wild dead animals and the closure of public areas (e.g., beaches) reporting high wildlife mortalities.

Risk distribution of human infections with avian influenza A (H5N1, H5N6, H9N2 and H7N9) viruses in China.

This study aimed to investigate epidemiologic characteristics of major human infection with avian influenza and explore the factors underlying the spatial distributions, particularly H5N6 and H9N2, as H9N2 could directly infect mankind and contribute partial or even whole internal genes to generate novel human-lethal reassortants such as H5N6. They pose potential threats to public health and agriculture. This study collected cases of H5N1, H5N6, H9N2, and H7N9 in China, along with data on ecoclimatic, environmental, social and demographic factors at the provincial level. Boosted regression tree (BRT) models, a popular approach to ecological studies, has been commonly used for risk mapping of infectious diseases, therefore, it was used to investigate the association between these variables and the occurrence of human cases for each subtype, as well as to map the probabilities of human infections. A total of 1,123 H5N1, H5N6, H9N2, and H7N9 human cases have been collected in China from 2011 to 2024. Factors including density of pig and density of human population emerged as common significant predictors for H5N1 (relative contributions: 5.3, 5.8%), H5N6 (10.8, 6.4%), H9N2 (11.2, 7.3%), and H7N9 (9.4, 8.0%) infection. Overall, each virus has its own ecological and social drivers. The predicted distribution probabilities for H5N1, H5N6, H9N2, and H7N9 presence are highest in Guangxi, Sichuan, Guangdong, and Jiangsu, respectively, with values of 0.86, 0.96, 0.93 and 0.99. This study highlighted the important role of social and demographic factors in the infection of different avian influenza, and suggested that monitoring and control of predicted high-risk areas should be prioritized.

Responding to avian influenza A H5N1 detection on a hospital property in Maine-An interdisciplinary approach.

The risk of infection with avian influenza A viruses currently circulating in wild and domestic birds in the Americas is considered low for the general public; however, detections in humans have been reported and warning signs of increased zoonotic potential have been identified. In December 2022, two Canada geese residing on the grounds of an urban hospital in Maine tested positive for influenza A H5N1 clade 2.3.4.4b. Given the opportunity for exposure to staff and hospital visitors through potentially infected faeces on the property, public health authorities determined mitigation efforts were needed to prevent the spread of disease. The ensuing response relied on collaboration between the public health and animal health agencies to guide the hospital through efforts in preventing possible zoonotic transmission to humans. Mitigation efforts included staff communication and education, environmental cleaning and disinfection, enhanced illness surveillance among staff and patients, and exposure and source reduction. No human H5N1 cases were identified, and no additional detections in birds on the property occurred. Hospital staff identified barriers to preparedness resulting from a lack of understanding of avian influenza A viruses and transmission prevention methods, including avian influenza risk in resident wild bird populations and proper wildlife management methods. As this virus continues to circulate at the animal-human interface, this event and resulting response highlights the need for influenza A H5N1 risk awareness and guidance for facilities and groups not traditionally involved in avian influenza responses.

A Clinicoradiological Profile of H3N2 Outbreak in Western India

Abstract Introduction: Although H3N2 outbreaks were once rare, they have become more common in recent years. With a significant toll on health-care resources and the ability to cripple any society, the epidemiological significance of this disease is paramount. While most of the previous studies on influenza outbreaks have reported H1N1 disease, there is a scarcity of literature regarding the H3N2 clinicoradiological profile. Hereby, we present the clinicoradiological profile of a series of H3N2 cases from western India. Materials and Methods: This is a retrospective chart-based review of clinicoradiological profile of a series of cases that were reported to a tertiary care center in western India between February 2023 and March 2023. Results: A total of 10 patients had tested positive for H3N2. All patients had a history of fever lasting an average of 4.7 days, and six had varying degrees of dyspnea. One patient had gastrointestinal symptoms, and six developed tachypnea with hypoxemia requiring oxygen supplementation. One patient with multiple comorbidities required invasive mechanical ventilation and had a complicated course with a superadded bacterial infection. Out of the four patients with radiographic findings, two had atypical pneumonia/acute infective etiology. Conclusion: This study provides valuable insights into the clinical presentation and management of H3N2 infections. The findings highlight the importance of influenza vaccination and early detection of H3N2 infections to prevent severe complications. The successful outcomes of the patients in this study demonstrate the effectiveness of prompt intervention and appropriate treatment in managing H3N2 infections.

Avian Influenza: Could the H5N1 Virus Be a Potential Next Threat?

Avian influenza virus (AIV) poses a significant challenge to poultry production, with negative repercussions for both the economy and public health worldwide. Since January 2003, a total of 868 human cases of AIV H5N1 have been reported from four countries in the Western Pacific Region, as of 9 March 2023. When AIVs are circulating in poultry, there is a risk of sporadic infections and small clusters of human cases due to exposure to infected poultry or contaminated environments. The increase in reported A(H5N1) infections may reflect continued virus circulation in birds, as well as enhanced surveillance and diagnostic capacity resulting from the response to the COVID-19 pandemic. Numerous countermeasures, including vaccines and antiviral treatments, are available for influenza infection. However, their effectiveness is often debated due to the ongoing resistance to antivirals and the relatively low and unpredictable efficiency of influenza vaccines compared to other vaccines. Vaccination remains the primary method for preventing influenza acquisition or avoiding serious complications related to the disease. In this review, we summarize the global landscape of the Influenza A virus and provide insights into human clinical symptomatology. We call for urgent investment in genomic surveillance strategies to timely detect and shape the emergence of any potential viral pathogen, which is essential for epidemic/pandemic preparedness.

Characterization of neurotropic HPAI H5N1 viruses with novel genome constellations and mammalian adaptive mutations in free-living mesocarnivores in Canada

ABSTRACT The GsGd lineage (A/goose/Guangdong/1/1996) H5N1 virus was introduced to Canada in 2021/2022 through the Atlantic and East Asia-Australasia/Pacific flyways by migratory birds. This was followed by unprecedented outbreaks affecting domestic and wild birds, with spillover into other animals. Here, we report sporadic cases of H5N1 in 40 free-living mesocarnivore species such as red foxes, striped skunks, and mink in Canada. The clinical presentations of the disease in mesocarnivores were consistent with central nervous system infection. This was supported by the presence of microscopic lesions and the presence of abundant IAV antigen by immunohistochemistry. Some red foxes that survived clinical infection developed anti-H5N1 antibodies. Phylogenetically, the H5N1 viruses from the mesocarnivore species belonged to clade 2.3.4.4b and had four different genome constellation patterns. The first group of viruses had wholly Eurasian (EA) genome segments. The other three groups were reassortant viruses containing genome segments derived from both North American (NAm) and EA influenza A viruses. Almost 17 percent of the H5N1 viruses had mammalian adaptive mutations (E627 K, E627V and D701N) in the polymerase basic protein 2 (PB2) subunit of the RNA polymerase complex. Other mutations that may favour adaptation to mammalian hosts were also present in other internal gene segments. The detection of these critical mutations in a large number of mammals within short duration after virus introduction inevitably highlights the need for continually monitoring and assessing mammalian-origin H5N1 clade 2.3.4.4b viruses for adaptive mutations, which potentially can facilitate virus replication, horizontal transmission and posing pandemic risks for humans.

Human death due to H5N1 amid the COVID-19 pandemic and Mpox outbreak: A call for action.

Human death due to H5N1 amid the COVID-19 pandemic and Mpox outbreak: A call for action.

Mild and asymptomatic influenza B virus infection among unvaccinated pregnant persons: Implication for effectiveness of non-pharmaceutical intervention and vaccination to prevent influenza.

We estimated symptomatic and asymptomatic influenza infection frequency in community-dwelling unvaccinated pregnant persons to inform risk communication. We collected residue sera from multiple antenatal-care blood draws during October 2016-April 2017. We determined influenza infection as seroconversion with≥4-fold rise in antibody titers between any two serum samples by improved hemagglutinin-inhibition assay including ether-treated B antigens. The serology data were linked to the results of nuclei acid testing (rRT-PCR) based on acute respiratory illness (ARI) surveillance. Among all participants, 43%(602/1384) demonstrated serology and/or rRT-PCR evidenced infection, and 44%(265/602) of all infections were asymptomatic. ARI-associated rRT-PCR testing identified only 10%(61/602) of total infections. Only 1%(5/420) of the B Victoria cases reported ARI and had a rRT-PCR positive result, compared with 33%(54/165) of the H3N2 cases. Among influenza ARI cases with multiple serum samples, 19%(11/58) had seroconversion to a different subtype prior to the illness. The incidence of influenza B infection in unvaccinated pregnant persons is under-estimated substantially. Non-pharmaceutical intervention may have suboptimal effectiveness in preventing influenza B transmission due to the less clinical manifestation compared to influenza A. The findings support maternal influenza vaccination to protect pregnant persons and reduce consequent household transmission.

Ventilator management in pregnant patients with H1N1 infection: Two case reports

The outbreak of H1N1, a virus of swine origin was detected in Mexico in late March and early April 2009. World Health Organization (WHO) in 2009 reported that 195 countries have reported confirmed human cases of H1N1. This pandemic virus infection though was self limited mild to moderate disease; there were reports of fatal complications especially in children and young adults. There was little or no immunity to this virus by humans and this virus targeted lower respiratory tract and caused pneumonia which was rapidly progressing. Approximately 10-30% of those infected with H1N1 required intensive care. Though the pandemic was declared to be over in August 2010, the concern of clinical management of H1N1 infected patient still remains challenging. The differences in presentation, clinical course and ventilatory management of two cases with pregnancy as a risk factor for complicated H1N1 infection are compared in this case report.

Fast COVID-19 versus H1N1 screening using Optimized Parallel Inception

COVID-19 and swine-origin influenza A (H1N1) are both pandemics that sparked significant concern worldwide. Since these two diseases have common symptoms, a fast COVID-19 versus H1N1 screening helps better manage patients at healthcare facilities. We present a novel deep model, called Optimized Parallel Inception, for fast screening of COVID-19 and H1N1 patients. We also present a Semi-supervised Generative Adversarial Network (SGAN) to address the problem related to the smaller size of the COVID-19 and H1N1 research data. To evaluate the proposed models, we have merged two separate COVID-19 and H1N1 data from different sources to build a new dataset. The created dataset includes 4,383 positive COVID-19 cases, 989 positive H1N1 cases, and 1,059 negative cases. We applied SGAN on this dataset to remove issues related to unequal class densities. The experimental results show that the proposed model’s screening accuracy is 99.2% and 99.6% for COVID-19 and H1N1, respectively. According to our analysis, the most significant symptoms and underlying chronic diseases for COVID-19 versus H1N1 screening are dry cough, breathing problems, diabetes, and gastrointestinal.

Global Epidemiology of Human Infections With Variant Influenza Viruses, 1959-2021: A Descriptive Study.

Although human case numbers of variant influenza viruses have increased worldwide, the epidemiology of human cases and human-to-human transmissibility of different variant viruses remain uncertain. We used descriptive statistics to summarize the epidemiologic characteristics of variant virus infections. The hospitalization rate, case-fatality, and hospitalization-fatality risks were used to assess disease severity. Transmissibility of variant viruses between humans was determined by the effective reproductive number (Re) and probability of infection following exposure to human cases. We identified 707 naturally infected cases of variant viruses from 1959 to 2021, and their spatiotemporal/demographic characteristics changed across subtypes. The clinical severity of cases of variant viruses was generally mild; patients older than 18 years with underlying conditions were associated with hospitalization. Of 69 clusters of human infections with variant viruses (median cluster size: 2), the upper limit of Re was 0.09 (H1N1v, H1N2v, and H3N2v: 0.20 vs 0.18 vs 0.05), whereas it was not significantly different from the pooled estimates for avian influenza A(H7N9) and A(H5N1) viruses (0.10). Moreover, contacts of H5N1 cases (15.7%) had a significantly higher probability of infection than contacts of individuals with H7N9 (4.2%) and variant virus infections (4.2%-7.2%). The epidemiology of cases of variant viruses varied across time periods, geographical regions, and subtypes during 1959-2021. The transmissibility of different variant viruses between humans remains limited. However, given the continuous evolution of viruses and the rapidly evolving epidemiology of cases of variant viruses, improving the surveillance systems for human variant virus infections is needed worldwide.

Highly pathogenic avian influenza in Bulgaria - a review

The aim of this review was to summarise the information about the cases of highly pathogenic avian influenza in Bulgaria during the last two decades. According to the EMPRES-I FAO data, from January 2006 to the end of 2019, 141 HPAI outbreaks have been registered in Bulgaria, with two identified virus serotypes (H5N1 and H5N8). The H5N1 outbreaks were reported in 2006, 2010 and 2015. Almost all H5N1 cases were observed in wild birds, with only one outbreak in domestic chickens in a backyard farm in 2015. From 2016 to the end of 2019, 132 outbreaks of HPAI identified as H5N8 were recorded: sixteen in wild birds and the other 116 - in domestic poultry. Large farms with fattening ducks used for foie gras production in four administrative districts (Plovdiv, Haskovo, Stara Zagora, Dobrich) were mainly affected.

Profile of Secondary Bacterial Respiratory Infections in H1N1 Patients Admitted in a Tertiary Care Centre - A Four-year Retrospective Study.

H1N1 is known to cause periodic seasonal flu in the Indian subcontinent since 2009. The clinical course and the underlying immunity of the host contribute to the development of secondary bacterial infections in the infected patients. This study aims to analyze the secondary bacterial infections in confirmed H1N1 cases admitted in our hospital (from 2015 to 2018) with respect to the comorbidities, complications, associated bacteria with its antibiotic susceptibility pattern, and the outcome of such episodes. Data of 164 patients admitted in a tertiary care hospital with H1N1 was extracted from medical records using a semi-structured case report form. Data were entered and analyzed with SPSS version 17. A p-value of <0.05 was considered statistically significant. Most patients were aged above 40 years with female preponderance. In our study, 42% of patients had comorbidities. Only 14 (8.53%) had secondary bacterial infection confirmed by culture. Klebsiella pneumoniae and Acinetobacter baumannii were the most common bacteria that were isolated. They were treated based on the culture reports. There was no mortality in patients with a secondary bacterial infection. The early start of the antiviral agents and adherence to the antibiotic policy of the hospital contributed to lower secondary bacterial infections and zero mortality.

Public health spending, primary care, and perceived risk promoted vaccination against H1N1

The purpose of this study is to examine factors affecting the intent to vaccinate during the 2009 H1N1 pandemic and to leverage the results to inform public health policy decisions aimed at increasing vaccine uptake during the COVID-19 pandemic. Using the National 2009 H1N1 Flu Survey data and state-level administrative data, we employ logistic regression and mediation models to estimate the association between vaccine uptake and state level public health spending, political ideology, and H1N1 case and death rates as well as a set of individual and household characteristics. We find that higher public health spending can significantly increase the intent to vaccinate, mainly through raising concerns about the pandemic and promoting vaccine relevant doctor patient interactions. We conclude that physicians, especially primary care physicians, should play more important roles in the ongoing vaccination efforts against the COVID-19 virus.

COVID-19: The New Reality

SPEAKER: Michael T Osterholm, PhD, MPH Director, Center for Infectious Disease Research and Policy Infectious Disease Research and Policy University of Minnesota REPORTER: Peter J Olson, ELS JAMA Network Let’s face it: We all need a good, old-fashioned reality check at one point or another, and this has never been more true than during the COVID-19 pandemic. In his keynote address on May 4, 2021, at the CSE 2021 Virtual Annual Meeting, Dr Michael Osterholm provided attendees with a frank and fact-laden overview of the current state of the pandemic as of May 2021 that was interwoven with his candid appraisals of the uncharted road ahead. Osterholm’s candor was manifest not only in the hard truths about the pandemic and the virus behind it, but also in his assertions about our ability—or lack thereof—to predict or control our fate. As is often the case, any discussion about the future is rooted in the events of the past, and this is where Osterholm started. Historically, our preparation for pandemics caused by respiratory-transmitted pathogens has been informed largely by our knowledge of the influenza virus and the many influenza pandemics that have transpired within the last century. Citing the 2009 pandemic caused by the H1N1 strain of the influenza virus, which emerged in Mexico and quickly spread to North America, Osterholm noted that the sharp surges and precipitous drops in H1N1 case numbers occurred without any human mitigation, and that the vaccine that was developed ultimately had little influence on the […]

H1N1 and COVID-19: surprising mortality pattern correlation

Background: Explanation of observed differentials in mortality rates during the COVID-19 pandemic across regions and countries is a great dilemma. To improve current and future pandemic response and to shed a light on secrets of COVID-19 mortality variances, we design this study to compare mortalities / million (M) between Covid-19pandemic and H1N1 2009 pandemic mortalities.Methods: One hundred thirty countries and territories that reported H1N1 cases up to September, 2009, were enrolled. COVID-19 accumulative deaths were considered up to January, 2021. Countries and territories &lt; 2 million inhabitants population at 2009 were excluded. We used simple regression analyses to test the associations (SPSS-21).Results: The pattern of variances in COVID-19 mortality rates across countries was surprisingly identical to the pattern of mortality rates across countries observed in H1N1 with meaningful linear regression tested in a two-tailed alternative statistical hypothesis. The slope value indicated that H1N1 deaths have a positive impact on COVID-19 mortality. with a very highly significant influence at p=0.0002. Relationship coefficient was accounted to (0.32789) with meaningful and a very high significant determination coefficient (R-Square = 10.75%). A very highly significant intercept (p=0.0000) reflects the severity of H1N1 and initial value even with no H1N1 deaths.Conclusions: We are adding another risk factor that can be used as a predictor for current and future epidemics.

Using demographic data to understand the distribution of H1N1 and COVID-19 pandemics cases among federal entities and municipalities of Mexico.

BackgroundThe novel coronavirus disease (COVID-19) pandemic is the second global health emergency the world has faced in less than two decades, after the H1N1 Influenza pandemic in 2009–2010. Spread of pandemics is frequently associated with increased population size and population density. The geographical scales (national, regional or local scale) are key elements in determining the correlation between demographic factors and the spread of outbreaks. The aims of this study were: (a) to collect the Mexican data related to the two pandemics; (b) to create thematic maps using federal and municipal geographic scales; (c) to investigate the correlations between the pandemics indicators (numbers of contagious and deaths) and demographic patterns (population size and density).MethodsThe demographic patterns of all Mexican Federal Entities and all municipalities were taken from the database of “Instituto Nacional de Estadística y Geografía” (INEGI). The data of “Centro Nacional de Programas Preventivos y Control de Enfermedades” (CENAPRECE) and the geoportal of Mexico Government were also used in our analysis. The results are presented by means of tables, graphs and thematic maps. A Spearman correlation was used to assess the associations between the pandemics indicators and the demographic patterns. Correlations with a p value < 0.05 were considered significant.ResultsThe confirmed cases (ccH1N1) and deaths (dH1N1) registered during the H1N1 Influenza pandemic were 72.4 thousand and 1.2 thousand respectively. Mexico City (CDMX) was the most affected area by the pandemic with 8,502 ccH1N1 and 152 dH1N1. The ccH1N1 and dH1N1 were positively correlated to demographic patterns; p-values higher than the level of marginal significance were found analyzing the % ccH1N1 and the % dH1N1 vs the population density. The COVID-19 pandemic data indicated 75.0 million confirmed cases (ccCOVID-19) and 1.6 million deaths (dCOVID-19) worldwide, as of date. The CDMX, where 264,330 infections were recorded, is the national epicenter of the pandemic. The federal scale did not allow to observe the correlation between demographic data and pandemic indicators; hence the next step was to choose a more detailed geographical scale (municipal basis). The ccCOVID-19 and dCOVID-19 (municipal basis) were highly correlated with demographic patterns; also the % ccCOVID-19 and % dCOVID-19 were moderately correlated with demographic patterns.ConclusionThe magnitude of COVID-19 pandemic is much greater than the H1N1 Influenza pandemic. The CDMX was the national epicenter in both pandemics. The federal scale did not allow to evaluate the correlation between exanimated demographic variables and the spread of infections, but the municipal basis allowed the identification of local variations and “red zones” such as the delegation of Iztapalapa and Gustavo A. Madero in CDMX.

Clinico-epidemiological profile of Influenza A H1N1 cases at a tertiary care institute of Uttarakhand.

Introduction:The swine (H1N1) virus responsible for worldwide pandemics since 2009 is now causing seasonal epidemics. Since then alarming spikes of swine flu cases have been reported from Uttarakhand every year. There are limited studies conducted in this Himalayan belt to evaluate the clinical and epidemiological profile of the patients admitted in tertiary care hospitals.Aims & Objectives:This study aims to summarize the clinical and epidemiological attributes of swine flu and to approximate the burden of Influenza A H1N1 (Swine Flu) cases in this Himalayan belt.Material and Methods:Clinical and epidemiological characteristics of influenza A H1N1 cases from October 2018 to April 2019 were retrospectively and descriptively analyzed using data from the Medical Records Section and the isolation ward at Shri Guru Ram Rai Institute of Medical and Health Sciences; Shri Mahant Indiresh hospital.Results:A total of 1126 (51.6%) patients were tested of which 30% (338) patients were found to be H1N1 positive. Maximum cases and positivity were detected in the months of January (26.4%), February (50.3%), and March (14.8%), and the patients in the age groups of 41–50 (21.9%) and 51–60 years (19.3%) accounted for majority of the cases. The most common symptoms were fever (85.8%), cough (82.2%), sore throat (82%), and breathlessness (71.3%). A case fatality ratio of 10.9% was observed. A significant statistical association (p value < 0.00001) was reported between co-morbid conditions and death.Conclusion:According to the results of this study, close caution should be exercised in case of patients infected with H1N1 particularly those with co-morbidities.

A Mathematical Modeling Study: Assessing Impact of Mismatch Between Influenza Vaccine Strains and Circulating Strains in Hajj.

The influenza virus causes severe respiratory illnesses and deaths worldwide every year. It spreads quickly in an overcrowded area like the annual Hajj pilgrimage in Saudi Arabia. Vaccination is the primary strategy for protection against influenza. Due to the occurrence of antigenic shift and drift of the influenza virus, a mismatch between vaccine strains and circulating strains of influenza may occur. The objective of this study is to assess the impact of mismatch between vaccine strains and circulating strains during Hajj, which brings together individuals from all over the globe. To this end, we develop deterministic mathematical models of influenza with different populations and strains from the northern and southern hemispheres. Our results show that the existence and duration of an influenza outbreak during Hajj depend on vaccine efficacy. In this concern, we discuss four scenarios: vaccine strains for both groups match/mismatch circulating strains, and vaccine strains match their target strains and mismatch the other strains. Further, there is a scenario where a novel pandemic strain arises. Our results show that as long as the influenza vaccines match their target strains, there will be no outbreak of strain H1N1 and only a small outbreak of strain H3N2. Mismatching for non-target strains causes about 10,000 new H3N2 cases, and mismatching for both strains causes about 2,000 more new H1N1 cases and 6,000 additional H3N2 cases during Hajj. Complete mismatch in a pandemic scenario may infect over 342,000 additional pilgrims (13.75%) and cause more cases in their home countries.

Trends in pattern of communicable diseases during COVID-19 lockdown in Kerala.

Dear Editor, Kerala is witnessing an increase in instances of vector-borne diseases and water-borne infections in recent times. [1] The state witnessed Nipah virus outbreak during 2018 and 2019. [2] COVID-19 pandemic surfaced in Kerala on 30 January 2020 and the cases increased during the month of March. [3] We performed a retrospective analysis of communicable disease reported in Kerala with the data retrieved from the website archive of Integrated Disease Surveillance Programme and tuberculosis notification website. [45] The incidence of various communicable diseases were compared during the study period (month of March, April and May 2020 where cases of COVID-19 were reported and containment strategies were implemented) with similar months for last four years (2016 to 2019) as per availability of the data. There was a decrease in the incidence of chickenpox cases by 22.3%, 21.5% and 66.3%, respectively, during the month of March, April and May 2020 in comparison with similar months of 2019. Tuberculosis cases decreased by 19.4%, 35.77% and 19.41% during the study period in comparison with similar months in 2019 [Table 1]. The incidence of H1N1, hepatitis A and typhoid cases decreased during the study period in comparison with similar months of 2019. There was a trend of increase in incidence of ADD cases during the month of May, but during 2020 the percentage increase was lowest among the last 4 years. Malaria and Chikungunya cases reported low but the incidence of dengue cases was slightly more in study period in comparison with similar period in 2019 [Table 1].Table 1: Incidence of communicable diseases in Kerala during the month of March, April and May 2016-2020.The containment strategies against COVID-19 in Kerala prevent the interaction between the agent and host in a favourable environment which helps to contain communicable diseases [Figure 1]. Overcrowding which was prevented by lockdown measures, life style and behavioural changes like social distancing, respiratory hygiene/cough etiquette helped to decrease other respiratory infections like tuberculosis, chickenpox and H1N1 along with COVID-19.Figure 1: Epidemiological triad showing the factors prevented the interaction between agent, host and environmentLockdown measures confined individuals at home which removed the possibility of food and water intake from contaminated environment and routine hand washing practices curtailed the intestinal diseases like hepatitis A, typhoid and acute diarrheal diseases. It was also noticed a decrease in malaria and chikungunya cases which may be due to the environmental sanitation measures underwent during the pandemic [Table 1]. The response of health system to the pandemic, its containment strategies which was implemented through community participation and intersectorial coordination along with lifestyle and behavioral modification of people helped in control of other communicable diseases in the state. There may be some other reasons also for the decrease in the incidence of communicable diseases as people might have ignored slight manifestations of the disease because of the fear to go to hospitals. Health system is overwhelmed with COVID-19 cases which may result in less testing and under reporting of other communicable diseases. Control of infectious diseases is a difficult challenge for our public health systems; however, we believe that covid-19 response and strengthened containment strategies had an impact on the incidence of communicable diseases which need to be carried over. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. Acknowledgement The authors thank Dr. Binod Kumar Patro, Additional Professor, AIIMS, Bhubaneswar for his guidance and review of the article.