Wednesday, August 4, 2010

Filariasis is Still Happening in Developing Countries

Preview Filariasis
Lymphatic filariasis (elephantiasis disease) is a chronic infectious disease caused by the filaria worm. The disease is transmitted by various species of mosquitoes. In 2004, an estimated one-fifth of the world's population or 1.1 billion people in 83 countries at risk of filariasis, particularly in tropical and subtropical areas. This disease can cause disability, social stigma, psychosocial barriers and decreased productivity of patients, families and communities, causing substantial economic losses. Patients with a burden of family and country.
Lymphatic filariasis elimination of global agreements have been reached with recommended resolutions by the World Health Assembly (WHA) on May 13th 1997 is "... ... Elimination lymphatic filariasis as a public health problem ... ... ..". Follow up the resolution, the WHO declared in 2000 the Global Goal Of Elimination Lymphatic Filariasis as a Public Health Problem by 2020. To achieve these objectives the need for epidemiologic picture that includes knowledge about the causes of disease (agent), humans susceptible (host) animals (reservoir hosts), the vector, the environment that influence the development of the disease, the chain of transmission and the situation of filariasis in Indonesia.
Although filariasis does not cause death but it is one cause of disability, poverty and other social problems. This is because in case of permanent disability is lifelong sufferer unable to work optimally, so that it can be a burden his family, to the detriment of society and state. The frequency of acute attacks in patients with filariasis is lowered work productivity so it can also harm the public. In addition, patients will experience an economic loss of approximately 17.8% of household expenses, or 32.3% of the cost of family meals.
Defect in patients with a clinical filariasis due to poor treatment of injured limbs or suffered swelling. Clinical filariasis patients affordable health services are usually no symptoms and severe disability, therefore, patients with chronic clinically severe and permanent disability bias is a poor, remote and inaccessible health services adequately.

The Cause of Filariasis
Indonesia's Filariasis caused by three species of filaria worms:
1. Wuchereria bancrofti
2. Brugia malayi
3. Brugia timori.

Microfilariae have a certain periodicity, that is, microfilariae in peripheral blood at certain times only. For example in W. Bancrofti are periodic nocturnal means numerous in the microfilariae in peripheral blood at night, while by day there are many capillaries in organs such as lung, heart and the kidney.
In epidemiological filaria worms were divided into 6 types, namely:
1. Wuchereria bancrofti urban types (urban)
Found in urban areas such as Jakarta, Bekasi, Tangerang, Semarang, Pekalongan, Indonesia and surrounding countries have a periodicity nokturna, transmitted by Culex quinquefasciatus mosquitoes are breeding in household waste water.

2. Type of rural Wuchereria bancrofti (rural)
Found in rural areas outside Java, particularly widespread in Papua and East Nusa Tenggara, the Indonesian state has periodicity nocturnal transmitted through a variety of mosquito species Anopheles, Culex and Aedes.

3. Type of periodic Brugia malayi nocturnal
Microfilariae are found in peripheral blood at night. Anopheles mosquitoes that spread it are found in areas barbirostis paddy fields.

4. Brugia Malay sub periodic type nocturnal
Microfilariae found in the peripheral blood on day and night, but were more common at night. Mosquitoes that spread it are Mansonia spp found in swamp areas.

5. Non-periodic Brugia malayi type
Microfilariae are found in peripheral blood both night and day. Mansonia mosquitoes transmitted is bonneae and Mansonia uniformis found in the jungle.

6. Timori type of periodic Brugia nocturnal
Microfilariae are found in peripheral blood at night. Anopheles mosquitoes that spread it are barbirostis found in rice cultivation areas in East Nusa Tenggara, Maluku Tenggara, Indonesia country.
Filaria worm morphology

In general, the three species of worm life cycle is no different. Parasite life cycle occurs in the human body and the bodies of mosquitoes. Adult worms (called makrofilaria) living in the tract and lymph nodes, while his son (called microfilariae) in the circulatory system.

1. Makrofilaria
Makrofilaria (adult worms) of cylindrical-shaped, smooth as creamy white yarn and live in the lymph system. Female worms are ovovivipar and measuring 55-100 mm x 0.16 mm, can produce millions of microfilariae. Smaller male worms  55 mm x 0.09 mm with a circular tail.

2. Microfilaria
Female adult worms after fertilization spend millions of children of worms called microfilariae. Microfilaria size 200-600 μm x 8 μm and have a glove. Microscopically, the morphology of microfilariae of species can be distinguished based on: the size and color gloves headroom on Giemsa staining, the core body composition, number and location of the core at the tip of the tail.

Brugia malayi
Wuchereria bancrofti
Brugia timori

Chain Transmission of Filariasis
Filariasis transmission can occur when there are three elements, namely:
1. A source of transmission, is human or host reservoir containing the microfilariae in the blood.
2. The existence of a vector, is mosquitoes that can transmit filariasis.
3. Humans are susceptible to filariasis.
Someone can be infected with filariasis, where a person gets a bite of infective mosquitoes, the mosquitoes containing infective larvae (larval stage 3 - L3). At the time of infective mosquito bites humans, the L3 larvae will exit from the proboscis and live in the skin surrounding the hole mosquitoes. At attract mosquitoes proboscis, L3 larvae will go through a mosquito bite wounds and move toward the lymph system. In contrast to the transmission of malaria and dengue, see the cause of filariasis transmission chain is not easily transmitted from one person to another in a particular area, so it can be said that a person can be infected with filariasis, if he gets a mosquito bite a thousand times.
L3 larvae Brugia malayi and Brugia timori will become adult worms in the period of approximately 3.5 months, while Wuchereria bancrofti takes approximately nine months.
Besides difficult occurrence of mosquito-to-human transmission, real ability to get the microfilariae when mosquitoes suck blood containing the microfilaria is also very limited, the mosquitoes that suck too much microfilaria can experience death, but if microfilariae are sucked too little can minimize the number of microfilariae that L3 larva will be transmitted.
Vector density, temperature and humidity affect the displacement of filariasis. Temperature and humidity affect the life of a mosquito, so that existing microfilaria in mosquito body is not enough time to grow into infective larvae L3 (extrinsic incubation period of parasites). Extrinsic incubation period of Wuchereria bancrofti to between 10 -14 days, while Brugia malayi and Brugia timori between 8 -10 days.
Periodicity of microfilariae and mosquito biting behavior influence infection risk. Microfilariae that are periodically nocturnal (microfilaria only found in the peripheral blood at night) has a vector that actively seek out the blood at night, so that transmission also occurs at night. In regions with sub-periodic microfilariae nocturnal and non-periodic, transmission can occur day and night.
In addition to the above factors, population mobility from filariasis-endemic areas to other areas or vice versa, the potential to become the media of inter-regional spread of filariasis.

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