Epidemiology of Chikungunya in Indonesia

Abstract

Chikungunya is a zoonotic disease which is caused by the Chikungunya virus (CHIKV) and transmitted by infected Aedes spp mosquito. In Indonesia, CHIKV is a re-emerging disease, which means that it is a disease that has gone for a long time, but then it spreads again and causes outbreaks frequently. CHIKV presence in Indonesia was first reported in 1979 in Bengkulu City causing substantial acute and chronic morbidity. After disappearing for 16 years, the CHIKV outbreak spreaded again in 24 regions throughout Indonesia from 2001 to 2003. In 2009 and 2010, CHIKV outbreaks hit western and central regions of Indonesia and increased from 3,000 cases per year to 83,000 and 52,000 cases per year. The burden of this disease is unclear due to insufficient monitoring and diagnosis. The spread and transmission of CHIKV in Indonesia is very high, due to travel, competent vectors, and the vulnerability of the population. In addition, the evolution of viruses, globalization and climate change has accelerated the spread of this virus. Effective antiviral treatment and vaccines do not yet exist, so early detection and appropriate management can help reducing the burden of this disease. Monitoring and risk assessment to reduce human-vector contact are also needed to reduce the impact of chikungunya.

1. Introduction

Chikungunya is a zoonotic disease caused by the Chikungunya virus (CHIKV), and transmitted by infected Aedes spp mosquito. CHIKV is an important but often overlooked cause of fever in the tropics and subtropics [1, 2]. The disease is of little interest in the medical community and causes less fear when compared to other arboviruses such as DENV. The reappearance of CHIKV after a long absence has only recently attracted global attention because of its explosive attack, rapid spread, high morbidity, and various clinical manifestations [3, 4, 5, 6]. However, the diagnosis of CHIKV is still very low due to overlapping clinical presentation with DENV and other endemic infections [7] as well as the lack of capacity for CHIKV testing [8]. Viral evolution, globalization, and climate change can further accelerate the spread of CHIKV, whereas specific antiviral treatments and effective vaccines do not yet exist [9].

In Indonesia, CHIKV is a re-emerging disease, which means that it is a disease that has gone for a long time, but it then spreads again [10]. Evidence from historical reports indicates that the first spread of CHIKV occurred in 1779 in Jakarta, but at that time the disease was referred to as kidinga pepo [11, 12]. This is widely recognized by arbovirus experts as the first report on chikungunya in Indonesia, although it cannot be proven by molecular analysis [13]. Virologically confirmed chikungunya outbreaks were first reported in June 1982 in Jambi province on the island of Sumatra, followed by outbreaks between 1983 and 1984 [14]. CHIKV was no longer recorded in Indonesia for about 20 years, before the infection re-emerged and caused several outbreaks in South Sumatra, Aceh and West Java in early 2001 [15]. In 2009 and 2010, CHIKV outbreaks hit western and central region of Indonesia started from approximately 3,000 cases per year increased to 83,000 and 52,000 cases per year [15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]. After 2010, detected cases fell to 3,000 per year. Except during outbreaks, the number of cases are likely to be underestimated because diagnosis is often based solely on clinical presentation [27, 28].

2. Epidemiology

Arboviruses are viruses that undergo a cycle of transmission between a blood-eating arthropod vector and reinforcing vertebrate host. Mosquitoes are the main vector of arbovirus transmission and human involvement in the transmission cycle is incidental [29]. It is estimated that 3.9 billion people in 120 countries are at risk of being infected with one of the three main arboviruses, namely: namely CHIKV, Dengue virus (DENV) and Zika virus (ZIKV) [30]. An outbreak of chikungunya with specific features was first reported in the Southern province of Tanzania’s Tanganyika region in 1952 [31, 32]. Later sporadic outbreaks of chikungunya were identified in parts of Africa and Asia during the 1950s and 1960s, followed by a clear comeback in the 2000s [33]. Since 2005, large-scale outbreaks of chikungunya have hit the southwest Indian Ocean and Southeast Asia [34, 35, 36, 37, 38, 39, 40, 41, 42, 43]. In La Réunion, the outbreak affected about a third of the population [35, 44], and in India the virus infected more than 1.3 million people during 2005–2006 [45] and CHIKV then spread to Southeast Asia including Indonesia.

3. Definition

The diseases caused by CHIKV are clinically difficult to distinguish and accurately diagnose from diseases caused by DENV solely on clinical symptomps [46, 47]. Although previous literature has shown that, the proportion of symptoms in people infected with CHIKV is higher than DENV [48], however a systematic review shows that asymptomatic chikungunya has very wide variability with a percentage of around 3,2% during 2005–2006 in La Réunion to 82,1% during 2012–2013 in Philippines [49]. The definition includes four categories of cases: (1). Clinical case of acute, characterized with fever (temperature above 38.5° C/101.3° F]) and arthritis or joint pain (sometimes disabling) with epidemiological criteria and/or acute onset and laboratory criteria; (2). Atypical case, characterized with laboratory confirmed clinical cases accompanied with other manifestations (ie, cardiovascula, neurological, ophthalmological, dermatological, hepatic, renal, respiratory, or conditions of hematological); (3). Cases of severe acute, characterized with laboratory-confirmed clinical cases of CHIKV with life-threatening abnormal function of minimal 1 organ or system and requiring inpatient; (4). Chronic cases of suspected/confirmed, characterized with a previous clinical diagnosis of chikungunya 12 weeks after onset of symptoms and indicating at least 1 rheumatological manifestation (ie, edema, stiffness, or pain) that was persistent or recurring [50].

The highest CHIKV genotype in Asia has been noted to be asymptomatic found in Philippines with a percentage of 82.1% [51]. Common symptoms of chikungunya include high fever, severe joint and muscle pain, rash, photophobia and headache [52, 53]. Severe symptoms implicated vital organs may develop during infection, like encephalitis [54, 55], myelopathy, myelitis [55], encephalopathy [55, 56, 57], neuroretinitis [58], optic neuropathy and Guillain’s Syndrome [55, 58]. Barré [55, 58], myocarditis [57], hepatitis [59], acute interstitial nephritis [60], severe sepsis, septic shock [61] and multi-organ failure [57, 58, 59, 62, 63]. In rare cases, infection can be fatal [44, 59, 60, 61, 63]. Perinatal CHIKV infection can cause symptoms such as microcephaly and cerebral palsy [64]. In adults with persistent arthralgia/arthritis, alopecia and depression are the other symptoms most frequently noted [65, 66, 67]. A meta-analysis found that about 25% of chikungunya cases caused chronic inflammatory rheumatism and 14% had chronic arthritis [68].

4. Incidence and mortality

Eleven annual reports from the Indonesian Ministry of Health (MoH) were identified between 2004 and 2019 [15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]. These data show that the lowest incidence rate of CHIKV occurred in 2005 with 0.16/100,000 person-years [15] while the highest incidence rate was recorded in 2009 to 36.2 cases per 100,000 person-years [23]. In 2009, more than 83 thousand cases CHIKV in Indonesia was reported circulating in 17 of 34 provinces (50%) [23]. Cases began to decline in 2010 with 52,703 cases and continued to decline significantly until 2018, but again increased in 2019 with an incidence of 5,042 cases (Figure 1), but some districts did not report cases of chikungunya [69]. Based on a report from the MoH, this increase was due to relatively humid weather conditions with high rainfall, long periods of rain and immunity in areas that had been affected [69].

Figure 1.

Trend and number of chikungunya cases based on the Ministry of Health report of the Republic of Indonesia from 2010 to 2019.

The case map by province showed that the CHIKV was not evenly distributed across Indonesia. The highest incidence of chikungunya occurred in Sumatra, Kalimantan and Java. However, Papua and West Papua provinces of Indonesia did not report chikungunya in 2008 and 2016. The shift in cases in several Indonesian provinces in 2019 has changed with the highest cases in West Java, Lampung and Gorontalo.

CHIKV cases that occurred in Indonesia during the 26 years period (1989–2014) actually originated from several countries. During that period there were 195 cases of chikungunya reported from travelers returning from Australia (128 cases) [70, 71, 72, 73, 74, 75, 76, 77] Taiwan (47 cases) [47, 78, 79], Japan (4 cases) [80, 81] and other countries. in Asia, Europe and the Pacific (16 cases) [82, 83, 84, 85, 86, 87, 88]. Based on the results of investigations on five outbreaks that occurred, there were no reports of deaths due to chikungunya [40, 45, 64, 89, 90]. In addition, in eleven annual reports from the Indonesian MoH, for 44 years (1973 to 2016) there were also no deaths related to CHIKV infection [39, 41, 42, 44, 46, 47, 48, 49, 51].

5. CHIKV genotype circulating in Indonesia

Sixteen studies that reported on the CHIKV genotype identified circulating in Indonesia were 130 viral sequences [27, 38, 47, 78, 79, 82, 87, 88, 91, 92, 93, 94, 95, 96, 97, 98]. There were seven studies conducted on local populations [27, 28, 38, 91, 93, 96, 98] and eight studies with viruses isolated from travelers returning from Indonesia [47, 78, 79, 83, 87, 88, 92, 97]. One study did not specify whether the virus was isolated in local residents or in travelers [82]. Of the seven studies, four were conducted in non-outbreak conditions [27, 28, 93, 96], two investigations were carried out during an outbreak of chikungunya [38, 91] and one study did not specify the condition [99]. Most of the viruses isolated from travelers originated in Taiwan [47, 78, 79]. Another virus was collected from travelers returning from Singapore [92], France [97], the Netherlands [82], Russia [83], and Germany [88]. Most of the CHIKV isolated from Indonesia belonged to the Asian genotype and partially from the ECSA genotype. Of these ECSA viruses, two were isolated from local residents in 2011 [38] and eight others were isolated from travelers returning from Indonesia between 2008 and 2010 [47, 87, 92]. The ESCA virus sample during the 2008–2011 period in Indonesia was included in the Indian Ocean Lineage (IOL) because in the same period it was also circulating in Southeast Asian countries such as China, South Korea, Malaysia, Sri Lanka, Thailand, Singapore, and Myanmar [93].

6. Vectors of CHIKV

The vector that plays a role in CHIKV and DENV is the Aedes aegypti mosquito and the potential vector is the Aedes albopictus mosquito (The Asian Tiger Mosquito) [25]. The Aedes mosquito is a mosquito that belongs to the Diptera order and has more than 950 species [100]. Transmission of the disease caused by the Aedes mosquito can manifest itself in humans and animals. The Aedes mosquito usually lives in temperate and tropical climates. However, due to the current uncertain climate change, this mosquito is able to expand its habitat [100]. The following is an explanation of the mosquito that transmits CHIKV:

6.1 Taxonomy

Kingdom: Animalia.

Phylum: Arthropoda.

Class: Insecta.

Order: Diptera.

Family: Culicidae.

Subfamily: Culicinae.

Tribes: Aedini.

Genus: Aedes.

Species: Aedes aegypti and Aedes albopictus.

6.2 Morphology

6.2.1 Adult Aedes aegypti Mosquito

The Aedes aegypti mosquito was first discovered in Southeast Asia and was identified in Malaysia and Thailand in the early 20th century. Apart from carrying CHIKV, these mosquitoes are also carriers of yellow fever and dengue fever. The body of the Aedes aegypti mosquito consists of the head, thorax and abdomen. On the head area there is a proboscis, antenna, maxillary palpus, and clype. On the thorax area there is the scutum, and at the end of the thorax is the scutellum. Proboscis in males is longer (0.76 ± 0.04 mm) than in females (0.53 ± 0.06 mm) but only in females the structure is formed to suck blood while males only suck nectar. The antennae in males are longer (0.57 ± 0.03 mm) and also have denser hair than females (0.52 ± 0.07 mm) [101, 102, 103]. Specific Characteristic of the adult mosquito Aedes aegypti is the scutum on the thorax is black or brown with a pair of submedian-longitudinal white stripes, but without median-longitudinal white stripes, or with white lute-shaped markings. Mesepimeron with two nicely separated white scale patches. The anterior part of the midfemur with longitudinal white stripes, and the head of the clypeus with white scales. In addition, paratergite with wide white scales and palpomeric heads 4 with white scales on apex [102, 104].

6.2.2 Adult mosquito Aedes albopictus

Aedes albopictus is a type of mosquito that is currently the main vector in various parts of the world. Moreover, these mosquitoes have the ability to transmit various diseases (acting as vectors) from arbovirus to worms such as Dirofilaria immitis and vector for 22 arboviruses [105]. Aedes albopictus is medium in size (2–10 mm) and the males are smaller than the females. The males can also be distinguished by their more feathered antennae than the females [106]. Its abdomen area is covered by black scales. The morphological characteristics of Aedes albopictus are slightly different from Aedes aegypti. Scutum thorax of this species is characterized with a narrow median-longitudinal white stripe. Mesepimeron with inseparable white scaly patches, forming a white V-shaped patch. The anterior part of the midfemur has longitudinal white stripes and the head of the clypeus without white scales [102].

6.2.3 Eggs

Female Aedes mosquitoes usually lay eggs on a substrate that is on the surface of the water either in artificial or natural water containers [107]. Aedes eggs are white and soft when laid but later turn black and become hard and increase in size [108, 109]. Eggs of Aedes aegypti and Aedes albopictus do not form groups, but individually and float on the surface of a wet substrate such as water [110, 111]. Aedes eggs can survive dry conditions for months or years [110] and also these eggs can have viability despite being faced with excessive water conditions [112, 113, 114]. Aedes eggs can withstand extreme conditions because they have a shell or what is called an eggshell that protects the oocyte, egg, embryo from extreme conditions but is still able to exchange enough gas to survive [107]. The difference between Aedes albopictus and Aedes aegypti lies in the difference of the micropylar collar shape, where Aedes aegypti’s eggs have a prominent micropylar collar and in Aedes albopictus it is not too striking. Aedes albopictus has a large tubercle in the middle so it looks like a smoother, lighter one than in Aedes aegypti.

6.2.4 Larvae

Aedes aegypti’s larvae usually have an oval head, a thorax and also an abdomen consisting of 9 segments. On the posterior side, there are 4 lobes and also a siphon which functions to help breathing on the water surface. On the surface of the water, Aedes larvae will have a hanging position almost forming a vertical direction [102]. Aedes aegypti has a specific characteristic that its 8th abdominal segment has comb scales equipped with lateral spines (Figure 2A). Furthermore, Aedes aegypti larvae also has pectent teeth on the siphon. In addition, Aedes aegypti larvae has 5 pairs of hairs on its ventral brush. In Aedes albopictus mosquito larvae, the brush scales do not have lateral spines, pecten teeth with two branches while the ventral brush has 4 unpaired hairs (Figure 2B).

Figure 2.

The differences of comb scale on A. aegypti dan A. albopictus [103, 104].

The life cycle of the Aedes albopictus mosquito is highly dependent on ambient temperature and pH of 5.2-7.6 with an optimal pH of about 6.8 and 7.6 in Asia [115]. Research conducted by Satoto, et al. States that the larvae of Aedes aegypti and Aedes albopictus can be found as much as 61% in flower pots, 15.38% bathtubs, containers, large and small buckets containing 55% water. Aedes albopictus larvae are active feeders, which means that they eat various kinds of organic matter in the water.

6.3 Bionomics

6.3.1 Breeding places

The breeding places habitats of the two vectors are somewhat different. For Aedes aegypti, its preferred place to lay eggs is in a clear water reservoir in the house, which is protected from the sun. Water reservoirs that can hold water for a long time make this habitat easy to breed [116, 117], such as bathtubs in bathrooms (toilets), bathtubs, drinking water reservoirs, buckets, jars, drums, and the like [101, 104, 118]. In Dar es Salaam, it is found in piped water systems due to intermittent water supply and rainwater storage which is used for community needs [119]. Aedes albopictus prefers to lay eggs in water reservoirs outside the house such as cans, bottles, discarded tires, tree holes, plant grooves, pieces of bamboo, and open coconuts. This shelter is not used for daily household needs. This is in accordance with the nature of Aedes aegypti which has a tendency as a house mosquito and Aedes albopictus which is an outdoor mosquito [100, 103, 117].

6.3.2 Feeding habit

The Aedes aegypti mosquito is anthropophagic, which means that it prefers to suck human blood in a single gonotrophic cycle [120]. While the Aedes albopictus mosquito is a more zoophagic, random bloodsucker [121], it has also been shown to exhibit strong anthropophagic behavior like Aedes aegypti [122]. To find their host, mosquitoes are active in the morning, which is around 8 am–10 am and in the afternoon 3 pm–5 pm [123]. Three days after sucking blood, female mosquitoes produce 100–200 eggs depending on the amount of blood sucked. The more blood it sucked, the more eggs will be produced [124].

6.3.3 Resting places

Places that mosquitoes prefer to rest while waiting to lay eggs are the ones which are dark, humidwith little wind [125]. Aedes aegypti prefers dark, damp, and hidden places in the house or building as a place to rest, including in the bedroom, in the bathroom, and in the kitchen. Indoors, a mosquito’s preferred resting surface is under the furniture, hanging objects such as clothes and curtains, and walls. These mosquitoes are rarely found outdoors, in plants, or other protected areas. Meanwhile, the Aedes albopictus mosquito, known as the Asian tiger mosquito, prefers places outside the house, such as in tree holes, plant grooves, and gardens or forest edge areas [118, 126, 127].

6.3.4 Flight range

The movement of Aedes aegypti mosquitoes from breeding places to prey and rest areas is determined by the ability of mosquitoes to fly. The average flight range of the Aedes aegypti mosquito is about 100 m, but in certain circumstances these mosquitoes can fly up to several kilometers in an attempt to find breeding places to lay their eggs. The mosquito Aedes albopictus has a flight range of 400-600 m [128].

Several studies have shown that the average mosquito has a flight range (mainly related to migration) between 50 m and 50 km [129]. Aedes albopictus, a type of mosquito that breeds in containers, is a very weak flyer (mean maximum 676 m) [130]. The flight ability of mosquitoes is highly dependent on wind assistance as some species can disperse during periods of high winds and energy required to travel great distances. For active flight Aedes aegypti and Aedes albopictus depend on carbohydrates [131].

7. Prognosis

A retrospective study of 107 serologically proven cases of chikungunya infection (CHIKV) was conducted. All respondents had contracted the disease at least 3 years before; 87.9% had fully recovered, 3.7% had only occasional stiffness or mild discomfort, 2.8% had residual joint stiffness but no pain, while 5.6% had persistent pain and stiffness and frequent effusions. All patients with persistent joint pain and stiffness had very high antibody titres against the CHIK virus [132]. In some isolation, CHIKV performed in severe cases showed bleeding manifestations, neurological abnormalities, and heart muscle abnormalities. Sports activities can worsen clinical symptoms such as joint pain, especially in the morning. The knee joint can swell as can the wrist and finger joints [133]. CHIKV infection, both clinical and silent, will provide lifelong immunity, so it is difficult for the same disease to attack the same patient [134]. Most patients recover completely from infection, but in some cases, joint pain can last for months, or even years [135].

8. Incubation period and treatment based on the natural course of the disease

8.1 Incubation period

The incubation period occurs when the mosquito acquires the virus from the viremic host. After an average extrinsic incubation of 10 days, the mosquitoes can then transmit the virus to a host, such as humans. In humans bitten by infected mosquitoes, disease symptoms usually appear after an intrinsic mean incubation period of three to seven days (range: 1–12 days) [115].

8.2 Acute and chronic

Symptomatic or supportive treatment, consisting of rest and use of acetaminophen or paracetamol to relieve fever, and ibuprofen, naproxen, or other non-steroidal anti-inflammatory agents (NSAIDs) to relieve the rheumatic component of the disease. In patients with severe joint pain that does not resolve with NSAIDs, narcotics (e.g. morphine) or short-term corticosteroids may be used after evaluating the risk–benefit of these treatments. Patients are advised to drink plenty of fluids to replace fluids lost through sweating, vomiting, and other involuntary fluid losses [136].

8.3 Sub-acute and chronic

Recovery from CHIK will be a fairly long process (sometimes up to a year or even more) and persistent joint pain may require pain management, including long-term anti-inflammatory therapy. Although studies have shown that chloroquine phosphate provides some benefit [137], randomized, double-blind placebo-controlled trials have shown that it is not useful for treating joint symptoms [138]. Apart from pharmacotherapy, cases of prolonged arthralgia and joint stiffness can be treated with a gradual physiotherapy program [136].

8.4 Isolation

To prevent transmission to other people in the household, community, or hospital, sufferers of acute chikungunya (CHIKV) should avoid being bitten by the Aedes aegypti or Aedes albopictus mosquitoes during the viremic phase, which is usually the first week of illness. In addition, doctors or health workers visiting patients infected with CHIKV at home must also be careful not to be bitten by mosquitoes by wearing repellents and wearing long sleeves and pants [136]. One hospital-related CHIK infection has been identified in a healthcare provider due to the accidental needle puncture of a CHIK patient [139]. Some laboratory personnel also contracted CHIKV infection after handling infected blood [140]. This exposure indicates that direct contact transmission can occur.

9. Surveillance of chikungunya

Epidemiological surveillance is the key to detecting cases in a timely manner and a prompt and appropriate response is required with the active participation of all stakeholders. Surveillance activities are carried out to determine whether chikungunya (CHIKV) has entered an area, track the disease that has entered and follow it on an ongoing basis. The forms of CHIKV surveillance activities in Indonesia are: [136, 141].

9.1 Case definition

The case definition of CHIKV used in the surveillance system in Indonesia has been published in the Ministry of Health’s National Guidelines for Chikungunya Prevention and Control followed World Health Organization (WHO) criteria [141]. In short, chikungunya cases are classified into three categories, namely: (1). Possible cases, diagnosed on clinical criteria alone as acute fever>38.5° C and severe arthralgia/arthritis which could not be explained by other medical conditions; (2). Probable cases, diagnosed based on clinical criteria as stated and epidemiological criteria (living or visiting epidemic areas); (3). Confirmed cases, diagnosed according to laboratory criteria that showed a positive result for viral isolation, RT-PCR, IgM antibody or a fourfold increase in IgG antibody.

9.2 Preparation phase

Strengthen the fever syndromic surveillance sentinel site, so that officers can detect cases of chikungunya (CHIKV). The percentage of patients presenting with fever and arthralgia or fever and arthritis with no known etiology (eg, testing negative for malaria or dengue), should be tested for CHIK in an adequate national referral laboratory [141].

9.3 Response phase

Once a case of chikungunya (CHIKV) is detected, an in-depth epidemiological investigation will be carried out to (1). Track the spread of viruses; (2). Monitor the possibility that cases have entered the surrounding area; (3). Describe the epidemiological features and main clinical features; (4). Assess the severity and impact on society; (5). Identify risk factors or factors that cause disease severity; (6) identify the circulating CHIKV lineage. These efforts will form the basis to develop effective control measures [136, 141].

9.4 Continuous transmission

Continuous surveillance to monitor changes in the epidemiology and ecology of CHIKV transmission. Any changes in surveillance at the national level should be communicated immediately to surveillance partners and other prevention units to ensure quality and uniformity of data collected [136, 141].

10. Vector surveillance and control

There are no specific antiviral treatments and vaccines that are effective yet, so the only method available to prevent infection is the reduction of human-vector contact [142]. We have done research about distribution of CHIKV vector transmission in Indonesia by taking locations that represent urban and rural areas, coastal and inland areas. The results of this study show on Aedes aegypti or Aedes albopictus or both were found in all sampling locations except in Warsadim, West Papua. Apart from Warsadim, there is only one site that does not have Aedes aegypti, namely Bugel in Yogyakarta Province, while 26 locations are free of Aedes albopictus [143]. Efforts to reduce CHIKV risk are carried out through an integrated vector management program component, including the following activities:

10.1 Vector monitoring and identification of high-risk areas

Retrospective analysis of dengue virus transmission in previous years can be carried out in the planning stage of chikungunya (CHIKV) to show areas where CHIKV is expected to circulate (given the similarities in the transmission cycle of this virus). Areas can be grouped in levels of risk of transmission, so they can be used to assign resources and priorities. For example, controlling or preventing transmission of CHIKV in the environment has resulted in many cases of dengue fever, thereby inhibiting viral amplification and spreading the virus to the immediate environment [144].

Programs should be able to systematically collect surveillance data for the vector density of Aedes aegypti and Aedes albopictus. The surveillance methods for Aedes aegypti and Aedes albopictus are quite varied and include a variety of methods to monitor egg production, larval location and density, pupa density, and adult mosquito density. This measure is used to asses the risk of outbreaks and to determine the appropriate vector control interventions [143]. Metodhs and tools, calculations and risk analysis with this measure have been widely discussed in the Dengue Hemorrhagic Fever guideline.

10.2 Self protection

Each individual can reduce the likelihood of transmission by using personal mosquito repellents. Babies and pregnant women who sleep or rest during the day should use a mosquito net. The use of insecticide-treated bed nets has the added benefit of killing mosquitoes that come into contact with the nets, thereby reducing vector-human contact with other household members. There are many insecticide products that can be used to treat mosquito nets safely or to make them last longer [136, 141, 142].

10.3 Prevention at the household and community level

The use of screened ventilation, or insulated windows and doors will reduce the entry of vectors into the house. Reducing and replacing containers that hold water over a long period of time can reduce vector breeding grounds [100, 104]. The number of adult mosquitoes in the home can be reduced by using commercially available aerosol sprays with pyrethroids and other household products, such as mosquito coils and electronics [145].

Prevention in community settings for CHIKV should be based on methods developed for dengue fever control to reduce vector mosquito density [146]. Dengue fever control programs that are carried out optimally will reduce the possibility of humans being infected when they come to an area that has the potential to cause secondary transmission and the formation of the virus. Dengue fever programs to control Aedes species that focus on larval control, often involving communities in environmental management and reduction of mosquito breeding sites [147]. However, community involvement has not been comprehensively incorporated into integrated vector management programs [147, 148].

11. Conclusion

The spread and transmission of CHIKV in Indonesia is very high due to its travel, competent vectors (the same vector as dengue fever), and the vulnerability of the population. Furthermore, the evolution of viruses, globalization and climate change has accelerated the spread of this virus. Timely case detection and prompt and appropriate response with active participation of all stakeholders are necessary to minimize cases of import and transmission that are increasingly widespread in Indonesia. The absence of treatments and effective vaccines makes the correct method for preventing infection is the reduction of human-vector contact through integrated vector management. Each of the discussions in this chapter can be used to improve early warning systems for detecting outbreaks, conducting epidemiological investigations, and preventing the spread of CHIKV.