Filariasis Vulnerability Zonation Based on Environmental and Behavioural Aspects in Pekalongan City, Indonesia

Pekalongan City is a filariasis endemic area in Central Java, Indonesia with Mf-rate >1%. It had held Mass Drug Administration (MDA) in 2011-2015. The evaluation result recommended it to re-hold MDA. This study aimed to compose filariasis vulnerability zonation based on environmental and behavioural aspects in Pekalongan City. The observed environmental aspects were the location of shrubs, cattle pen and tidal flood. The surveyed behavioural aspects were applicating mosquito repellent and hanging clothes habits. Filariasis cases data were collected from health office. This was a descriptive quantitative study with spatial approach. The environmental and behavioural aspects were observed and surveyed in 6 urban villages (38 RWs) with 387 households as samples which were chosen with proportional random sampling. The instruments were checklist sheets, Global Positioning System (GPS), satellite imagery and GIS software. Data were analysed with scoring, buffering and overlaying procedures. Results indicated some areas were categorized as highly vulnerable where shrubs, cattle pen, tidal flood and hanging clothes habit were present. It was concluded that all urban villages in this study had highly vulnerable RWs which are very potential for filariasis transmission. Applicating mosquito repellent habit was not potential aspect for controlling filariasis transmission in the studied areas.


Introduction
Filariasis is a systemic infection caused by filarial worms whose adult stages live in the lymph glands and human blood, then are transmitted through mosquitoes (i.e. Culex sp., Anopheles sp., Aedes sp., Armigeres and Mansonia). Filariasis is chronic and will cause permanent disabilities such as enlargement of the legs, arms, breasts, and genitals in women or men. Filariasis is caused by 3 species of filarial worms, such as Wuchereria bancrofti, Brugia malayi and Brugia timori [1]. The disabilities will decrease the productivities [2], [3]. Filariasis risk factors are related to mosquito's life and behavior. Previous studies had proven that lack of knowledge, poor sewerage condition, stagnant water existence, cattle pen existence and shrubs existence contribute to be the breeding and resting places for mosquitoes. Some behaviors are also proved to ease filariasis transmission, like hanging clothes, doing night outdoor Previous studies in the urban villages indicated that there were many potential breeding and resting places for mosquitoes and the community still practice unsafe behavior relating to filariasis transmission [11]- [15].
The community does not realize that they live surrounded by potential factors of filariasis transmission. The health officers also need any tool which can ease them to give more understandable and arousable information. Some researchers had tried to compose simulation and other predicting instruments for determining the risk of filariasis transmission or also preventing filariasis transmission [16], [17]. Those sometimes are not familiar to the common people and difficult to understand. Visual media could be more understandable [18]. Khikmah & Pawenang (2018) had compose filariasis risk vulnerability zone mapping in the studied urban villages based on review to sewerage condition, presence of stagnant water, night outdoor habit and using mosquito net habit [19]. There are some environmental and behavioral aspects which are not included yet in the mapping from Khikmah & Pawenang (2018) that it is needed to complete it.
This study aimed to compose filariasis vulnerability zonation based on environmental and behavioral aspects in the studied urban villages. The chosen urban villages were villages with Mf-rate >1% namely Banyurip Ageng Village, Jenggot Village, Bandengan Village, Pabean Village, Kuripan Lor Village and Kertoharjo Village. They are in Pekalongan Utara District and Pekalongan Selatan District. The observed environmental aspects were the location of shrubs, cattle pen and tidal flood. The surveyed behavioral aspects were applicating mosquito repellent and hanging clothes habits.

Methodology
Data were collected from 6 urban villages. These urban villages were chosen based on their filariasis cases number and Mf-rates in the periods before. They are Kertoharjo Village, Jenggot Village, Pabean Village, Kuripan Lor Village, Bandengan Village and Banyurip Ageng Village. Banyurip Ageng Village, Kertoharjo Village, Jenggot Village and Kuripan Lor Village are urban villages in Pekalongan Selatan District, whereas the rest are urban villages in Pekalongan Utara District. Urban villages consist of some RWs. RW is Rukun Warga which consists of some RTs. RT is Rukun Tetangga which consists of 60-100 households. The 6 studied urban villages consist of 38 RWs. Samples were chosen with proportional random sampling. The total population of the 6 urban villages is 11,070 households. Samples number was determined by calculating using random sampling formula and took 387 households. This was a descriptive quantitative study with spatial approach. The instruments were checklist sheets, Global Positioning System (GPS), satellite imagery and GIS software. The observed environmental aspects were the location of shrubs, cattle pen and tidal flood. Their coordinates were mapped. The surveyed behavioral aspects were applicating mosquito repellent and hanging clothes habits. RWs were colored on map based on the percentages of samples which had "good practice" criteria for behavior aspects. The filariasis cases data were collected from health office and mapped according to their coordinates. ArcGIS software was used to process the analytical steps. Data were analyzed with scoring, buffering and overlaying procedures. The final scoring of the environmental behavioral aspects was obtained from the multiplication results between the scores and the weight criteria of each aspect. Frequency distribution of behavior aspects were compared to the vulnerability level limits. Vulnerability zonation classifying was determined with Sturgess Formula. Vulnerability zonation was classified into 3 categories, i.e. highly vulnerable, moderately vulnerable and not vulnerable.

Results and discussion
The data of shrubs vulnerability were obtained only from Pekalongan Selatan District (Figure 1a). A vegetation object could be assessed as shrubs when it has minimally 2 m of height and 4 m 2 of large area. Vegetation objects in Pekalongan Utara District did not meet the criteria to be assessed as shrubs. Every village in Pekalongan Selatan District had their highly vulnerable RW(s). The most vulnerable RW was RW 2 of Banyurip Ageng Village. It had 100% buffer coverage and 100% filariasis cases in its Village. The data of tidal flood vulnerability were obtained only from Pekalongan Utara District because it has sea border in the north side (Figure 1b). Pekalongan Selatan District had no tidal flood case because it has no sea border. RW 13 of Pabean Village was the most vulnerable from all highly vulnerable RWs because it had 100% buffer coverage and 28.57% filariasis cases in its village.
Mapped cattle pen were cattle of cows and goats (Figure 1c and 1d). Every village in both Pekalongan Utara District and Pekalongan Selatan District had its highly vulnerable RW(s) for cattle pen vulnerability. RW 2 of Banyurip Ageng Village is the most vulnerable RW in Pekalongan Selatan District whose 100% filariasis cases in its villahe and 97% buffer coverage. RW 13 of Pabean Village was the most vulnerable RW in Pekalongan Utara District whose 76.89% buffer coverage and 28.57% filariasis cases in its village.
Applicating mosquito repellent habits vulnerability was described in Figure 1e and 1f. There were two RWs in Pekalongan Selatan District with highly vulnerable status because of their 30% coverage of applicating mosquito repellent habits, in contrary, they had no filariasis cases. There was not highly vulnerable RW in Pekalongan Utara District for applicating mosquito repellent vulnerability.
Hanging clothes habits vulnerability was illustrated in Figure 1g and 1h. This habit was verified when one hangs after use clothes for more than 1 day. Every village in the both districts had their highly vulnerable RW(s). They were RW 12 and RW 15 of Pabean Village, RW 5 of Bandengan Village, RW 1-6 of Banyurip Ageng Village, RW 1 and RW 4 of Kuripan Lor Village, RW 5,7 and 10 of Kertoharjo Village and RW 2, 4 and 11 of Jenggot Village. Figure 2 described the composite vulnerability status of filariasis transmission. Figure 2 indicated both Pekalongan Selatan District and Pekalongan Utara District had highly vulnerable RW(s) in each village. Bandengan Village had its RW 5 as highly vulnerable zone for filariasis transmission, whereas Pabean Village had its RW 13, Banyurip Ageng Village had its RW 2, Kertoharjo Village had its RW 9, Jenggot Village had its RW 3 and RW 11, and Kuripan Lor had its RW 3. RW 5 of Bandengan Village had its highly vulnerable status from variables of cattle pen, tidal flood, hanging clothes habits, and had 18.8% of filariasis cases in its village. RW 13 of Pabean Village had its highly vulnerable status from variables of cattle pen, tidal flood and had 28.57% of filariasis cases in its village. RW 2 of Banyurip Ageng had its highly vulnerable status from variables of shrubs, cattle pen, hanging clothes habits and had 100% of filariasis cases in its village. RW 9 of Kertoharjo Village had its highly vulnerable status from variables of shrubs, cattle pen and had 89.47% of filariasis cases in its village. RW 3 of Jenggot Village had its highly vulnerable status from variables of shrubs, cattle pen, hanging clothes with no filariasis cases. RW 11 of Jenggot Village had its highly vulnerable status from variables of shrubs, cattle pen, hanging clothes habits and had 71.42% of filariasis cases in its village. RW 3 of Kuripan Lor Village had its highly vulnerable status from variables of shrubs and cattle pen with no filariasis case.