Our aim was to obtain knowledge of how meteorological conditions affect community epidemics of respiratory syncytial virus (RSV) infection. To this end we recorded year-round RSV activity in nine cities that differ markedly in geographic location and climate. We correlated local weather conditions with weekly or monthly RSV cases. We reviewed similar reports from other areas varying in climate. Weekly RSV activity was related to temperature in a bimodal fashion, with peaks of activity at temperatures above 24-30 degrees C and at 2-6 degrees C. RSV activity was also greatest at 45-65% relative humidity. RSV activity was inversely related to UVB radiance at three sites where this could be tested. At sites with persistently warm temperatures and high humidity, RSV activity was continuous throughout the year, peaking in summer and early autumn. In temperate climates, RSV activity was maximal during winter, correlating with lower temperatures. In areas where temperatures remained colder throughout the year, RSV activity again became nearly continuous. Community activity of RSV is substantial when both ambient temperatures and absolute humidity are very high, perhaps reflecting greater stability of RSV in aerosols. Transmission of RSV in cooler climates is inversely related to temperature possibly as a result of increased stability of the virus in secretions in the colder environment. UVB radiation may inactivate virus in the environment, or influence susceptibility to RSV by altering host resistance.

Respiratory syncytial virus (RSV) is the most commonly identified viral agent of acute respiratory tract infection (ARIAcute respiratory tract infection (ARI) is the leading killer of children in the world (1.9 million per year), with the greatest number of deaths occurring in developing countries (49). Onefourth (2.5 million) of the total deaths among children less than 5 years of age occur in India (1), and approximately 20% of these are due to ARI (0.5 million) (35,49). Viruses are found in 20 to 40% of children hospitalized with ARIs in India, with respiratory syncytial virus (RSV) being one of the most frequently identified pathogens (15,22,23).RSV strains vary genetically and antigenically and have been classified into two broad groups, groups A and B (2,11,16,25), with additional variability detected within the groups (4, 40). Antigenic variability is thought to contribute to the capacity of the virus to establish reinfections throughout life and may pose a challenge to vaccine design. Future planning for vaccine development will require an understanding of the genetic composition of the RSV strains circulating among target populations.The RSV G protein is a type II integral membrane protein (48) and shows the highest degree of divergence both between and within the two groups (16). The G protein is highly glycosylated, and it is the target for neutralizing and protective immune responses. Variability in the G protein gene is concentrated in the extracellular domain, which consists of two hypervariable regions separated by a central conserved region of 13 amino acids (16). The second variable region, which corresponds to the C-terminal region of the G protein, reflects overall G protein gene variability and has been analyzed in molecular epidemiological studies (5, 33).The objective of the present study was to evaluate the genetic diversity of RSV strains collected in a longitudinal study of ARI from young children in two rural villages in India and from children with ARI seen in an urban hospital. Information about distribution of RSV genotypes in India will be beneficial to the development and implementation of RSV vaccines. MATERIALS AND METHODSClinical samples and diagnosis of RSV infection. The details of this epidemiological study will be described in another report that is under preparation; the results of the molecular epidemiologic study are provided here. Newborns from two rural villages, Nawadha and Mujheri, of Ballabgarh block near Delhi, were enrolled between October 2001 and December 2004 and monitored up to 3 years of age or to the end of the study, March 2005. Two hundred eighty-one children were enrolled, and the total follow-up was 441 child-years. The children enrolled in the study were seen weekly in their homes; approximately 85% of these visits were completed. ARIs were classified according to World Health Organization definitions (50), and nasopharyngeal aspirates (NPAs) were collected at each episode of ARI. ARI was defined as the presence of a cough or difficulty in breathing tha...

BackgroundAcute respiratory infection (ARI) is a major killer of children in developing countries. Although the frequency of ARI is similar in both developed and developing countries, mortality due to ARI is 10–50 times higher in developing countries. Viruses are common causes of ARI among such children, yet the disease burden of these infections in rural communities is unknown.Methodology/Principal FindingsA prospective longitudinal study was carried out in children enrolled from two rural Indian villages at birth and followed weekly for the development of ARI, classified as upper respiratory infection, acute lower respiratory infection (ALRI), or severe ALRI. Respiratory syncytial virus (RSV), influenza, parainfluenza viruses and adenoviruses in nasopharyngeal aspirates were detected by direct fluorescent antibody testing (DFA) and, in addition, centrifugation enhanced culture for RSV was done. 281 infants enrolled in 39 months and followed until 42 months. During 440 child years of follow-up there were 1307 ARIs, including 236 ALRIs and 19 severe ALRIs. Virus specific incidence rates per 1000 child years for RSV were total ARI 234, ALRI 39, and severe ALRI 9; for influenza A total ARI 141, ALRI 39; for INF B total ARI 37; for PIV1 total ARI 23, for PIV2 total ARI 28, ALRI 5; for parainfluenza virus 3 total ARI 229, ALRI 48, and severe ALRI 5 and for adenovirus total ARI 18, ALRI 5. Repeat infections with RSV were seen in 18 children.Conclusions/SignificanceRSV, influenza A and parainfluenza virus 3 were important causes of ARI among children in rural communities in India. These data will be useful for vaccine design, development and implementation purposes.

BackgroundMalaria, Dengue and Chikungunya are vector borne diseases with shared endemic profiles and symptoms. Coinfections with any of these diseases could have fatal outcomes if left undiagnosed. Understanding the prevalence and distribution of coinfections is necessary to improve diagnosis and designing therapeutic interventions.MethodsWe have carried out a systematic search of the published literature based on PRISMA guidelines to identify cases of Malaria, Dengue and Chikungunya coinfections. We systematically reviewed the literature to identify eligible studies and extracted data regarding cases of coinfection from cross sectional studies, case reports, retrospective studies, prospective observational studies and surveillance reports.ResultsCare full screening resulted in 104 publications that met the eligibility criteria and reported Malaria/Dengue, Dengue/Chikungunya, Malaria/Chikungunya and Malaria/Dengue/Chikungunya coinfections. These coinfections were spread over six geographical locations and 42 different countries and are reported more frequently in the last 15 years possibly due to expanding epidemiology of Dengue and Chikungunya. Few of these reports have also analysed distinguishing features of coinfections. Malaria/Dengue coinfections were the most common coinfection followed by Dengue/Chikungunya, Malaria/Chikungunya and Malaria/Dengue/Chikungunya coinfections. P. falciparum and P. vivax were the commonest species found in cases of malaria coinfections and Dengue serotype-4 commonest serotype in cases of dengue coinfections. Most studies were reported from India. Nigeria and India were the only two countries from where all possible combinations of coinfections were reported.ConclusionWe have comprehensively reviewed the literature associated with cases of coinfections of three important vector borne diseases to present a clear picture of their prevalence and distribution across the globe. The frequency of coinfections presented in the study suggests proper diagnosis, surveillance and management of cases of coinfection to avoid poor prognosis of the underlying etiology.Electronic supplementary materialThe online version of this article (10.1186/s12889-018-5626-z) contains supplementary material, which is available to authorized users.

Incidences of emerging/re-emerging deadly viral infections have significantly affected human health despite extraordinary progress in the area of biomedical knowledge. The best examples are the recurring outbreaks of dengue and chikungunya fever in tropical and sub-tropical regions, the recent epidemic of Zika in the Americas and the Caribbean, and the SARS, MERS, and influenza A outbreaks across the globe. The established natural reservoirs of human viruses are mainly farm animals, and, to a lesser extent, wild animals and arthropods. The intricate “host-pathogen-environment” relationship remains the key to understanding the emergence/re-emergence of pathogenic viruses. High population density, rampant constructions, poor sanitation, changing climate, and the introduction of anthropophilic vectors create selective pressure on host-pathogen reservoirs. Nevertheless, the knowledge and understanding of such zoonoses and pathogen diversity in their known non-human reservoirs are very limited. Prevention of arboviral infections using vector control methods has not been very successful. Currently, new approaches to protect against food-borne infections, such as consuming only properly cooked meats and animal products, are the most effective control measures. Though significant progress in controlling human immunodeficiency virus and hepatitis viruses has been achieved, the unpredictable nature of evolving viruses and the rare occasions of outbreaks severely hamper control and preventive modalities.