Dengue Epidemiology: Seasonal Trends in Tangub City | InformativeBD

Geographical location of the study area. Inset is  the map of the Philippines highlighting the Province of  Misamis Occidental (upper right) and the City of Tangub (lower right).

Erlyn B. Ladesma  , Quineybel N. Mag-usara  , Lea Mae G. Matu-og  , and Monaliza Joy Zaragoza-Magsayo from the different institute of the philippines wrote a research article about "Dengue Epidemiology: Seasonal Trends in Tangub City"entitled Seasonal variability on the epidemiology of Dengue in Tangub City, Misamis Occidental, Philippines, this research paper published by the International Journal of Biosciences |IJB  an open access scholarly research journal on Biology under the affiliation of the International Network For Natural Sciences |  INNSpub an open access multidisciplinary research journal publisher.

Abstract

Seasonal variability contributes to the abundance of dengue mosquito vector. In this study, the prevalence rate of dengue on different seasons, by population characteristics and geographical location in the City of Tangub were determined. Dengue cases and climatological information from 2016-2021 were obtained through secondary data gathering. Based on the data, dengue cases are highest on the year 2019. Specifically, dengue was more prevalent during rainy period. In terms of gender and age, males with ages of 10 to 19 were more prone to contracting dengue. Notably, for the last six-years dengue was predominant in built-up areas. The association between climatological factors and dengue incidence was further determined. On hot season, the heat index (-0.12) and precipitation (-0.04) is negatively correlated to dengue cases. While heat index and dengue cases on rainy season have no correlation, precipitation revealed a weak positive correlation (0.04) towards dengue infection. And on cool-dry season, heat index and precipitation showed a weak positive (0.4) and weak negative correlation (-0.10) to dengue cases, respectively. Generally, the climatological variables show no significant correlation (p>0.05) towards dengue cases. This paper revealed that dengue is highest during rainy days however, climatological factors are not reliably considered as effective predictors to dengue cases.

Introduction

Dengue  is  a  significant  health  challenge  that  is widespread  in  more  than  a  hundred  nations encompassing an estimation of three hundred ninety (390)  million  infected  individuals  annually  (Bhatt,2013).  Transmission  of  dengue  viral  infection  are carried  by  the  family  Flaviviridae  specifically  dengue vector Aedes  mosquito  (Edillo,  2012).  The  annual infection  rate  of  dengue  still  increases  due  to  factors such  as  population  growth,  urbanization,  inadequatepublic   health   infrastructure,   poor   solid   waste management,  and  inconsistent  preventive  practices (Aurelio et  al.,  2018).  According  to  World  Health Organization  (2014),  Philippines  rank  fourth  among the  ten  Southeast  Asian  Nations  at  higher  risk  of dengue infection. In fact, dengue had become endemic in different regions and results to a major public health problem in the Philippines (Herriman, 2017). 

Furthermore,  the  virus  disproportionately  affects children  and  young  people,  with  73%  of  recorded cases under the age of 19 (Muyot, 2019). In contrast, epidemiological  review  of  Bravo  (2011)  shows  that prevalence  rate  was  highest  among  children  ages between  5-14  years  old  and  over  80%  of  dengue-related  deaths  in  the  Philippines  occurred  among people under the ages of 20. For the prevalence rate of  dengue  cases  based  on  gender,  according  to  the data  reported  by  the  national  surveillance  systems adolescent and young adult males are found to be athigh risk of dengue (Arima, 2011). Gender differences in reported dengue surveillance data may be due to the exposure-associated  behaviors  or  activities,  such  as working-age  males  exposed  to  outdoor  environments during  the  day  when  dengue  virus-infected Aedes aegypti mosquitoes  are  active  (Yew et  al.,  2009; Prasith,  2013).  The  difference  in  the  male  to  female morbidity  rates  was  associated  with  the  difference in the  proportion  of  working  males  and  females, indicating  that  the  risk  of  dengue  increased  with  the increasing time spent away from home (Ooi, 2006). 

Seasonal   variability   encompasses   climatological factors   such   as   temperature,   humidity,   and precipitation contribute to the abundance of denguevector  (Xu et  al.,  2017).  Southeast  Asian  countries potentially have a high risk of dengue transmission due to  its  subtropical  humid  monsoon  climate  (Halstead,2006).  In  the  Philippines,  dengue  is  considered  as seasonal occurring diseases as it is notifiable during the rainy and cool-dry season (June-February). According from the studies of Wai et al. (2012) and Tsuzuki et al. (2009),  rainy  and  dry  seasons  has  a  tendency  to increase  mosquitos'  activity  in  growth,  survival,  and transmission as both seasons serve as a good breeding site for their growth and development. 

The  warming  of  the  climate  increases  the  risk  of dengue transmission. Some areas in Tangub City havebeen  affected  by  changes  in  the  weather  patterns which result in extreme heat and heavy rains that lead to flooding incidents. This phenomenon significantly influences  the  dengue  mosquito  vectors’  replication, growth,  and  rapid  transmission.  Tangub  is  also considered  as  a  growing  city  due  to  its  increasing population and building of infrastructures like the on-going  project  of  Panguil  Bay  Bridge.  Similarly,  theanticipated  urbanization  may  lead  to  the  resident’spoor  solid  waste  management  practices.  These contributing factors are evident in the city, resulting to an adaptive habitat of dengue. At present, no study has been conducted related to seasonal occurrences of dengue  in  Tangub  City.  In  this  context,  this  study intends to interpret which season dengue is prevalent, determine  the  age  and  gender  that  are  more susceptible  to  dengue  infection  and  identify  the geographical  area  prone  to  dengue.  The  findings  of this study will serve as basis for the local governments to  enhance  formulated  preventive  measures  and create  strategic  plan  to  raise  community  awareness subsequently,  improving  both  preparedness  and response activities during dengue outbreaks. Check out more by following the link Seasonal variability on the epidemiology of Dengue in Tangub City, Misamis Occidental, Philippines