Vol. 9 No. 1 January–April 2021 IJTID, p-ISSN 2085-1103, e-ISSN 2356-0991 Available online at IJTID Website: https://e-journal.unair.ac.id/IJTID/ Original Article Correlation between Climate Factors with Dengue Hemorrhagic Fever Cases in Surabaya 2007 – 2017 1,3 Faculty of Medicine of Universitas Airlangga, Surabaya, Indonesia 2 Departement of Public Health, Faculty of Medicine of Universitas Airlangga, Surabaya, Indonesia Received: 22nd January 2019; Revised: 4th February 2019; Accepted: 9th February 2021 ABSTRACT Dengue Hemorrhagic Fever (DHF) is a disease caused by dengue virus. DHF is mediated by the mosquito vector, the Aedes mosquito. The proliferation of dengue vector is influenced by many factors, one of which is climate factors. DHF is one of the main public health problems in Indonesia. Cases of dengue were first discovered in 1968 in the city of Jakarta and Surabaya. Currently Surabaya is one of the dengue endemic areas in Indonesia. . The case of DHF in the city of Surabaya can be said to be still quite high compared with another city in Indonesia, although there is a decrease in the number from year to year. When examined, many factors influence the high number of dengue cases in Surabaya, one of which is climate factor. Climate factors play a role in the proliferation of DHF vectors. Therefore, this study aims to examine for 10 years, namely in 2007 - 2017 whether there is a correlation between climate factors with dengue cases in the city of Surabaya., which in this study the climate factors used are rainfall, average temperature, and average air humidity. This research uses an analytical method namely Spearman on the SPSS software version 20. The results obtained that the case of DHF in the city of Surabaya has no relationship with climatic factors such as rainfall and average temperature with a significance value of the relationship p> 0.05. While the climate factor that has a relationship with DHF cases in Surabaya City is air humidity with a significance value of p <0.05 and has a positive relationship with the value of r = + 0.190. It can be concluded that not all climate factors have a relationship with the DHF case in Surabaya in 2007 - 2017, which has a relationship with the DHF case is air humidity. ABSTRAK Demam Berdarah Dengue (DBD) merupakan penyakit yang disebabkan oleh virus dengue. DBD diperantarai oleh vektor nyamuk yaitu nyamuk Aedes. Perkembangbiakan vektor demam berdarah ini dipengaruhi oleh banyak faktor salah satunya adalah perubahan iklim. DBD merupakan salah satu masalah kesehatan utama masyarakat di Indonesia. Kasus demam berdarah pertama kali ditemukan pada tahun 1968 di Kota Surabaya. Saat ini Surabaya merupakan salah satu daerah endemis DBD di Indonesia. Kasus DBD di Kota Surabaya sendiri dapat dikatakan masih cukup tinggi apabila dibandingkan dengan kota lain di Indonesia walaupun terlihat ada penurunan jumlah dari tahun ke tahun. Apabila ditelaah, banyak faktor yang mempengaruhi masih tingginya kasus DBD di Kota Surabaya, yang salah satunya adalah faktor iklim. Faktor iklim berperan dalam perkembangbiakan vektor DBD. Maka dari itu, penelitian ini bertujuan untuk meneliti selama 10 tahun, yaitu tahun 2007 – 2017 apakah ada hubungan antara faktor iklim dengan kasus DBD di Kota Surabaya, yang pada penelitian ini faktor iklim yang digunakan adalah curah hujan, suhu rata-rata, dan rata-rata kelembaban udara. Penelitian ini menggunkan metode analitik yaitu Spearman pada perangkat SPPS versi 20. Didapatkan hasil bahwa kasus DBD di Kota Surabaya tidak mempunyai hubungan dengan faktor iklim berupa curah hujan dan suhu rata-rata dengan nilai signifikansi hubungan p>0.05. Sedangkan faktor iklim yang memiliki hubungan dengan kasus DBD di Kota Surabaya merupakan kelembaban udara dengan nilai signifikansi p<0.05 serta memiliki hubungan yang positif dengan nilai r = + 0.190. Dapat disimpulkan tidak semua faktor iklim mempunyai hubungan dengan kasus DBD Kota Surabaya tahun 2007 – 2017, yang memiliki hubungan dengan kasus DBD adalah kelembaban udara. Kata kunci: Kasus DBD; Faktor iklim; Kelembaban udara, Surabaya, 2007 - 2017 * Corresponding Author: nadhilahp@gmail.com Open acces under CC-BY-NC-SA Share alike 4.0 Keywords: DHF case; climate factors; humidity; Surabaya; 2007 - 2017 Nadhilah Putri Ghaisani1*, Sulistiawati2, Maria Lucia Inge Lusida3 Nadhilah Putri Ghaisani, et al.: Correlation between Climate Factors with Dengue Hemorrhagic 40 IJTID, p-ISSN 2085-1103, e-ISSN 2356-0991 How to Cite: Ghaisani, NP., Sulistiawati., Lusida, MLI. Correlation between Climate Factors with Dengue Hemorrhagic Fever Cases in Surabaya 2007 – 2017.. Indonesian Journal of Tropical and Infectious Disease, 9(1), 39–44 INTRODUCTION Dengue hemorrhagic fever (DHF) is a disease caused by dengue virus carried by female Aedes mosquitoes, especially Aedes aegepty and a few Aedes albopictus.1 Dengue is widespread in the tropics and subtropics, including Indonesia. Dengue is one of the main health problems in Indonesia.2 DHF cases first appeared in Indonesia, namely in Jakarta and Surabaya in 1968.3 DHF Incidence Rate (IR) in Indonesia from 1968 - 2015 continue to increase.4,5,6,7,8,9 Dengue cases found in all provinces in Indonesia.10 One of the things that influences this phenomenon is the climate change. Climate change causes changes in rainfall, temperature, humidity, and air direction, thus affecting the terrestrial and oceanic ecosystems and also health.11 Climate change has a role in DHF vector.12 Aedes mosquitoes live in urban habitat and breed specifically in containers. Water needs for breeding is very important. It reach its peak during the rainy season.13 This mosquito tend to bite in the morning until noon. DHF has a strong correlation with the climate because the incidence of DHF usually happens on the beginning and the end of the rainy season.14 Very high rainfall influences the population of mosquitoes. Increased rainfall intensity refers to the increasing place of mosquitoes to breed, resulting in increasing mosquitoes population. Increasing the mosquito population increases the risk of female mosquitoes carrying the pathogens which will transmit to the next host.15 Aedes mosquito reproduction cycle will be shorter at temperatures higher than 32°C so that the mosquito population will multiply with increasing temperature 16. Warm temperatures also accelerate the metabolic process so that the frequency of biting will increase.17 The maximum temperature for mosquito growth is 25- 27°C. 18 Humidity affects the flight behavior and host search, mosquito life span and mosquito reproduction.17 High humidity helps the process of mosquito metabolism which will indirectly increase the frequency of biting. MATERIALS AND METHODS In Surabaya, the incidence of DHF in the 2007-2017 period as a whole has decreased in numbers although not stable. In below, figure 1 show the number of DHF cases in Surabaya from 2007 until 2017. Figure 1. Number of DHF cases in Surabaya in 2007 – 2017 From the data obtained a significant increase occurred in 2010, 2013, and 2016. If it is associated with the time of the El Nino occurrence, in those years the El Nino events that occur in the moderate and strong category. From previous study, there was an increase in the incidence of DHF when the El Nino with the same category occur. This research is an analytical study that uses secondary data in the form of institutional administrative data, namely the report of the Meteorology Climatology and Geophysics Agency (BMKG) and the Surabaya City Health Office with a cross-sectional approach. The sampling technique in this study uses a total sampling technique. The data were taken is the BMKG of Surabaya City weather report in 2007-2017 and the Surabaya City Health Office report on the incidence of dengue cases in 2007-2017. The collected data is grouped by month in each year and is written using tables and graphs and analyzed descriptively and tested statistically the correlation using Spearman method on the SPSS software version 20. RESULT AND DISCUSSION DHF Cases Profile in Surabaya Open acces under CC-BY-NC-SA Share alike 4.0 IJTID, p-ISSN 2085-1103, e-ISSN 2356-0991 41 Indonesian Journal of Tropical and Infectious Disease, Vol. 9 No. 1 January–April 2021: 39–44 Judging from the graph above in Figure 2, the same pattern was formed in 2007 - 2009. Starting from 2011 to 2017 the number of dengue cases began to decrease so that the pattern formed had changed from before. Whereas in 2010, 2013, and 2016 have different patterns from other years. Overall, from September to December the number of dengue cases has always been lower than in previous months. Figure 2. Cases of DHF per month each year Based on Surabaya City rainfall data for 2007-2017 in Figure 3, December to March were months with high rate of rainfall, while July to September were months with low rainfall. However, in 2010, 2013 and 2016 there was a change in the pattern in which high rate of rainfall occurred throughout the year even in the month that was supposed to be the peak of the dry season, making the accumulation of rainfall in those years the highest among the other years. Figure 4. Average temperature each year Figure 3. Rainfall per month each year Surabaya has monsoonal rain type that is influenced by west and east monsoon winds where the peak of the rainy season occurs in January, and the peak of the dry season occurs in August.19 0 100 200 300 400 500 600 Jan Feb Mar Apr Mei Jun Jul Agst Sept Okt Nov Rainfall 2007 2008 2009 2010 2011 2012 2013 2014 Rainfall Distribution of Surabaya Average Temperature Distribution of Surabaya City The average temperature of Surabaya City for the last 11 years is within normal range when compared to the 30-year data with an average value of 28,62oC. 28 28.2 28.4 28.6 28.8 29 29.2 29.4 29.6 Temperature (oC) From the graph in Figure 4, 2011 became a year with the lowest average temperature with a value of 28,6oC, while 2016 was a year with the highest average temperature of 29,4oC. The humidity of the city of Surabaya for the last 11 years is within normal range when compared to the 30-year data with a value of 74,33. From the graph in Figure 5, 2009 became the year with the lowest humidity with a value of 69,58 and 2017 became the year with the highest average humidity with a value of 76,92. Humidity Distribution of Surabaya City Open acces under CC-BY-NC-SA Share alike 4.0 Nadhilah Putri Ghaisani, et al.: Correlation between Climate Factors with Dengue Hemorrhagic 42 IJTID, p-ISSN 2085-1103, e-ISSN 2356-0991 The effect of rainfall on the incidence of DHF cases is complex, because it is influenced by several other factors.20 Rainfall has an influence on the vector growth, which is the density of adult mosquitoes. High rainfall intensity will cause the breeding site of adult mosquitoes to increase, which in turn increase the density of mosquitoes.15 However, in a short period, heavy rain will destroy mosquito larvae and reduce the survival rate of female mosquitoes.16 Table 1. Spearman Correlation Test Result Variable Mean ± SD p Rainfall 138,265 ± 131,269 0,159 DHF Cases 136,71 ± 135,560 From the result of published study in Table 1, the correlation test using Spearman obtained relationship significance of p >0.05. It can be interpreted that there was no correlation between rainfall and the incidence of DHF cases in Surabaya in 2007-2017. However, it must be noted that incidence of DHF cases is influenced by other factors besides than rainfall, such as humidity, evaporation of water, wind speed, and cloudiness.20 These results supported previous study in Surabaya which showed no significant fluctuations in certain months of the year regarding the number of dengue cases. These results are also similar with studies in other influ influencing factors.20 In addition, changes in rainfall patterns can also affect human behavior which will later affect lifestyle that further affect the dynamics of Aedes mosquito populations, for example, a change in water storing habit.20 However, studies assessing the correlation of rainfall with the incidence of DHF is not suitable to use the Spearman method. Spearman is suitable for measuring linear and static relationships, while the correlation between weather and DHF events is neither linear nor static.18 This can happened because from the previous study, the correlation between rainfall and the incidence of DHF has several conditions, such as regular rain that may cause an increase in dengue cases, whereas heavy rainfall does not. 18,21 So, the correlation bertween DHF cases and rainfall are not linear nor static. The results of this study supported previous studies in the city of Surabaya which showed no significant fluctuations in certain months of the year regarding the number of dengue cases. C Figure 5. Humidity in Surabaya City per year Correlation between Rainfall with DHF Cases Correlation between Temperature and DHF Cases Based on previous study, temperature has a role in the transmission cycle of dengue virus.21 Research in Thailand and Singapore showed that there was a correlation between temperature and the incidence of DHF cases. 22,16 Table 2. Spearman Correlation Test Result Variable Mean ± SD p Temperature 28,909 ± 0,739 0,066 DHF Cases 136,71 ± 135,560 Correlation test results in Table 2 showed the relationship significance of p >0.05 which means there was no correlation between temperature and the incidence of DHF in the city of Surabaya in 2007-2017. Similar to correlation of rainfall with the incidence of DHF cases, the relationship with temperature is also not a linear relationship or static, thus making this method not suitable for this case.18 It can be seen that the temperature data used is the average temperature, whereas the temperature is not only measured from the average Open access under CC-BY-NC-SA Share alike 4.0 IJTID, p-ISSN 2085-1103, e-ISSN 2356-0991 43 Indonesian Journal of Tropical and Infectious Disease, Vol. 9 No. 1 January–April 2021: 39–44 average value but there is also a minimum and maximum temperature. This minimum or maximum temperature value may also affect the presence or absence of its relationship with the incidence of DHF. Research that uses an epidemiological approach states that in certain months, high temperatures will cause mosquito populations to increase with low virus transmission, which usually causes an increase in virus transmission under conditions of high rainfall, low temperatures, and high humidity. 23 Humidity affects the flight behavior of mosquitoes by increasing the metabolism of the mosquito's body which then increase the biting behavior.24 Table 3. Spearman Correlation Test Result Variabel Mean ± SD p Humidity 73,48 ± 5,614 0,029 DHF Cases 136,71 ± 135,560 The correlation test results in Table 3 showed the relationship significance of p <0.05 which means there was a significant correlation between the two variables. The strength of the relationship between the two variables is very weak and the direction of the relationship is positive (r =+0.190). It can be interpreted that the higher the humidity, the higher the incidence of DHF. Similar to current study which showed that air humidity has a relationship with the incidence of DHF cases through the effect on the density of the dengue virus vector, the Aedes aegepty mosquito and the external incubation period of the dengue virus itself, thereby increasing its transmission. 23 accumulation followed by an increase in the incidence of dengue cases. Previous studies showed that there was a correlation between the increase in the incidence of DHF cases with the phenomenon of El-Nino-Southern Oscillation (ENSO) which is a cycle of sea surface temperature in the Pacific Sea. From the results of studies in Venezuela, 2009 - 2010 were the year with moderate El-Nino category, while 2014-2016 were the year with strong El-Nino or Mega Nino. 24 Within those 3 years, there was a recorded climate phenomenon that does not usually occur in Surabaya. During those years, dengue fever cases in the city of Surabaya also showed an increase in number. This result is linear with the previous study, that there is a significant relationship between ENSO and dengue incidence.25 Correlation between Humidity with DHF Cases Correlation between ENSO and DHF Cases Based on the available data, year of 2010, 2013 and 2016 were the year with high rainfall d CONCLUSION The climate factor which has an analytical correlation with the DHF case in Surabaya in 2007 - 2017 is humidity, while the climate factor such as rainfall and temperature does not have an analytical correlation with the DHF incidence rate. There is an influence of the El-Nino phenomenon on the number of DHF cases in Surabaya in a certain year. CONFLICT OF INTEREST There is no conflict of interest of this study. REFERENCES 1. Halstead, S. (2008). Dengue Virus–Mosquito Interactions. Annual Review of Entomology. 2008; 53(1), pp.273-291 2. Karyanti, M. and Hadinegoro, S. Perubahan Epidemiologi Demam Berdarah Dengue di Indonesia. Sari Pediatri. 2009; 10(6) 3. Nathan, M. and Harun, S. Dengue haemorrhagic fever and Japanese B encephalitis in Indonesia.. [online]. 2019. Europepmc.org. Available at: https://europepmc.org/abstract/med/2851186 4. Ministry of Health of the Republic of Indonesia. Infodatin (Pusat Data dan Informasi Kementerian Kesehatan RI). Available at: http://www.depkes.go.id/resources/download/pusdat in/infodatin/infodatin-dbd-2016.pdf Open access under CC-BY-NC-SA Share alike 4.0 Nadhilah Putri Ghaisani, et al.: Correlation between Climate Factors with Dengue Hemorrhagic 44 IJTID, p-ISSN 2085-1103, e-ISSN 2356-0991 5. Ministry of Health of the Republic of Indonesia. Infodatin (Pusat Data dan Informasi Kementerian Kesehatan RI). Available at: http://www.depkes.go .id/resources/download/profil/PROFIL_KAB_KOA _2016/3578_Jatim_Kota_Surabaya_2016.pdf. In Situasi DBD di Indonesia. 2016: 1–12 6. Ministry of Health of the Republic of Indonesia. Infodatin (Pusat Data dan Informasi Kementerian Kesehatan RI). Available at: http://www.depkes.go. id/resources/download/profil/PROFIL_KAB_KOT A_2015/3578_Jatim_Kota_Surabaya_2015.pdf 7. Ministry of Health of the Republic of Indonesia. Infodatin (Pusat Data dan Informasi Kementerian Kesehatan RI). Available at: http://www.depkes.go .id/resources/download/profil/PROFIL_KAB_KOT A_2014/3578_Jatim_Kota_Surabaya_2014.pdf.201 4: 1–6 8. Ministry of Health of the Republic of Indonesia. Infodatin (Pusat Data dan Informasi Kementerian KesehatanRI).Availableat:http://www.depkes.go.id/r esources/download/profil/PROFILKAB_KOTA_20 13/3578_Jatim_Kota_Surabaya_2013.pdf. 2013 9. Ministry of Health of the Republic of Indonesia. Infodatin (Pusat Data dan Informasi Kementerian Kesehatan RI). Available at: http://www.depkes.go .id/resources/download/profil/PROFIL_KAB_KOT A_2012/3578_Jatim_Kota_Surabaya_2012.pdf [Accessed 9 Apr. 2018]. 2012 11. Harapan, H., Michie, A., Mudatsir, M., Sasmono, R. and Imrie,A. Epidemiology of dengue hemorrhagic fever in Indonesia: analysis of five decades data from trhe National Disease Surveillance. BMC Research Notes. 2019; 12(1) 12. Hii, Y., Rocklöv, J., Ng, N., Tang, C., Pang, F. and Sauerborn, R. Climate variability and increase in intensity and magnitude of dengue incidence in Singapore. Global Health Action. 2009; 2(1), p.2036 13. Harapan, H., Michie, A., Mudatsir, M., Sasmono, R. and Imrie,A. Epidemiology of dengue hemorrhagic fever in Indonesia: analysis of five decades data from trhe National Disease Surveillance. BMC health. [online] 2018. Available at: https://www. who.int/newsroom/factsheets/detail/climate-change- and-health [Accessed 18 March 2018] 15. Lowe, R., Stewart-Ibarra, A., Petrova, D., García- Díez, M., Borbor-Cordova, M., Mejía, R., Regato, M. and Rodó 15. Valdez, L., Sibona, G. and Condat, C. Impact of rainfall on Aedes aegepty population. Ecological Modelling, 2018; 385: 96-105 16. Chumpu, R., Khamsemanan, N. and Nattee, C., The association between dengue incidences and provincial-level weather variables in Thailand from 2001 to 2014. Plos One. 2019; 14(12): e0226945 17. Reinhold,J., Lazzari,C. and Lahondere, C. (2018). Effects of the environmental Temperature on Aedes aegepty and Aedes albopticus Mosquitoes: A Review. Insects, 9(4), p.158 18. Ehelepola, N., Ariyaratne, K., Buddhadasa, W., Ratnayake, S. and Wickramasinghe, M. (2015). A study of the correlation between dengue and weather in Kandy City, Sri Lanka (2003 -2012) and lessons learned. Infectious Diseases of Poverty. 2015; 4(1) 19. BMKG | Badan Meteorologi, Klimatologi, dan Geofisika. Artikel : Karakteristik Rata-rata Suhu Maksimum dan Suhu Minimum Stasiun Meteorologi Nabire Tahun 2006-2015 | BMKG. 2018. [online] Available at: http://www.bmkg.go .id/artikel/?id=xa9q99255011rged5919 20. Choi, Y., Tang, C., McIver, L., Hashizume, M., Chan, V., Abeyasinghe, R., Iddings, S. and Huy, R. Effects of weather factors on dengue fever incidence and implications for interventions in Cambodia. BMC Public Health. 2016; 16(1) 21. Lai, Y. The climatic factors affecting dengue fever outbreaks in southern Taiwan: an application of symbolic data analysis. BioMedical Engineering OnLine. 2018; 17(S2) 22. Campbell, K., Lin, C., Iamsirithaworn, S. and Scott, T. The Complex Relationship between Weather and Dengue Virus Transmission in Thailand. The American Journal of Tropical Medicine and Hygiene. 2013; 89(6): 1066-1080 23. Sintorini, M. (2018). The correlation between temperature and humidity with the population density of Aedes aegypti as dengue fever’s vector. IOP Conference Series: Earth and Environmental Science. 2018; 106: 012033 24. Ninphanomchai, S., Chansang, C., Hii, Y., Rocklöv, J. and Kittayapong, P. Predictiveness of Disease Risk in a Global Outreach Tourist Setting in Thailand Using Meteorological Data and Vector- Borne Disease Incidences. International Journal of Environmental Research and Public Health. 2014; 11(10) : 10694-10709 25. Vincenti-Gonzalez, M., Tami, A., Lizarazo, E. and Grillet, M. (2018). ENSO-driven climate variability promotes periodic major outbreaks of dengue in Venezuela. Scientific Reports, 8(1) Open access under CC-BY-NC-SA Share alike 4.0 , X. Climate services for health: predicting the evolution of the 2016 dengue season in Machala, Ecuador. The Lancet Planetary Health. 2017; 1(4), pp.e142-e151 Research Notes. 2019; 12(1) 14. World Health Organization. Climate change and 10. Halstead, S. Dengue Virus–Mosquito Interactions. Annual Review of Entomology. 2008; 53(1), pp.273- 291 http://www.depkes.go/ http://www.depkes.go/ http://www.depkes.go/ http://www.depkes.go/ http://www.bmkg/