Dengue is a severe arthropod-borne viral disease that affects human health across the world (1–3). The manifestation of dengue is varied, ranging from a flu-like disease dengue fever (DF) to dengue hemorrhagic fever (DHF), which can progress to be a fatal type of dengue syndrome shock (DSS). More than 3.6 billion population live in tropical and subtropical countries where dengue viruses spread the disease. A total of 3.97 billion people living in 128 countries were at risk of dengue; in detail, 824 million people lived in urban residences, and 763 million people lived in peri-urban houses in 2012. Approximately 50–200 million dengue infections, 500,000 severe dengue cases (DHF/DSS), and more than 20,000 mortality cases were reported annually (4).
Dengue remains a health problem in Malang, which is the second-largest city in East Java Province, Indonesia. Urban areas in Malang are generally affected by dengue fever, with an increasing number of cases each year (5). Data showed that dengue cases are higher in urban than in rural area. It was supported by surveillance study in Malang in 2010 that urban areas were at highest risk for larvae finding than the rural area, which is potential to transmit dengue (6). According to the Public Health Official of Malang, the dengue cases increase every year. There were 160 dengue patients with one mortality case in urban areas in 2014. Further, three mortality cases occurred among181 dengue patients from January to December 2015 (5,7).
Ministry of Health of Indonesia has several strategies and programs to control the spreading of dengue infection. Since 1992, the Ministry has launched several approaches, including surveillance system, case management, vector control, and behavior intervention. Vector control and behavior intervention are combined with the surveillance system. This program is a must to be carried out periodically by the public and known as 3M plus that are menguras bak mandi (clean the water tub/container), menutup (cover the water container), membakar atau mendaur ulang (bury or recycle the water container). Meanwhile, the ‘plus’ means to combat mosquito nests (8–10). In 2016, Indonesia had a Healthy Indonesia program that is the strategy used to strengthening health services through a family approach. The role of the family is to continuously improve the Eradication of Mosquito Nest movement that is to monitor, inspect, and eradicate mosquito larvae. This concept is called "Satu Rumah Satu Jumantik” (One House One Larva Inspector)11. The success of mosquito nest eradication activity can be measured using free larva index. When the free larva index is higher or equal to 95%, it is expected that the transmission of dengue fever could be prevented. This popular index is the opposite of House Index.
Health volunteers have an essential role in controlling dengue. They are members of the larva monitoring team to observe larva in every home and public places, provide health promotion to families and public, and record and report the results of periodic larval results weekly and monthly. Besides, they also have to record and report the incidence of dengue cases to either cluster heads or Primary Health Care (Puskesmas)10,12.
Aedes aegypti breeding ground is usually in a pool of clean water. This breeding ground can be divided into three that are temporary, permanent, and natural. This mosquito can live in water drains, flower vases, used tin cans, used bottles, bathtubs, water barrels, and places where there are standing water12. Entomology Index is a measure of Ae. aegypti larvae density indicators in one particular settlement and serves as an essential consideration in determining effective vector control efforts. Successful implementation of larvae monitoring is in terms of the value from the House Index (HI), Container Index (CI), and Breteau Index (BI) because the entomology index is used to monitor the population density of Ae. aegypti in the spread of dengue virus. The index in dengue vector mosquito larvae is expressed in three types of indices determined by the World Health Organization (WHO) namely HI, CI, and BI. An area is said to be at high risk of DHF transmission if CI ≥ 10% and HI ≥ 5%, and it is said to have high potential of DHF transmission if BI is higher than 13. Therefore, this study aimed to identify the risk of dengue transmission in the urban areas of Malang and the key container which could be the breeding ground for mosquito.