Filariasis as a Mysterious Disease - Essay Example

Filariasis Thesis: Filariasis remain a mysterious disease for most people but for some, a lingering affliction that can only be resolved by unending research for new diagnostic tools, great dedication and team work and proper education by both patients and health workers. [Name] [Course] [Professor’s name] [Date] Abstract Although filariasis is infrequently fatal, it is the second principal cause of permanent and long-term disability in the world. Although difficult, but this disease is eradicable. The symptoms of some specific and common forms of filariasis can be discussed in more detail. Symptoms usually vary, depending on what type of parasitic worm has caused the infection, but most of the time all infection start with symptoms like chills, headache, and fever between three months and one year after the insect bite. There may also be swelling, redness, and pain in the arms, legs, or scrotum at the early stages. As far as the diagnosis of filariasis is concerned Identification of microfilariae by microscopic examination is the most practical diagnostic procedure. Examination of blood samples will allow identification of microfilariae of Wuchereria bancrofti, Brugia malayi and Brugia timori. It is important to time the blood collection with the known periodicity of the microfilariae. The blood sample can be a thick smear, stained with Giemsa or hematoxylin and eosin. More recently a new type of diagnosis process has emerged, known to be as cytodiagnosis. A number of evidences have been put forwarded by a number of researchers showing its efficiency. However, time has not come to claim that it is the best methods although at present it seems to be very effective. Whether cytodiagnosis would be the most effective diagnosis process or not, people have be very conscious about the disease filariasis and should take proper medication if infected, and proper preventative measures to reduce the probability of being infected. Introduction: Filariasis is known to be as a group of diseases, mainly found in and sub-tropical regions, caused by a variety of parasitic round worms (nematodes) and their larvae. The disease is transmitted to human body by the larvae through a mosquito bite. Filariasis is generally characterized by a number of symptoms like fever, chills, headache, and skin lesions in the early stages. If filariasis remains untreated, it results in gross enlargement of the limbs and genitalia, which is called elephantiasis. (Sasa, 1976) In Southeast Asia, South America, Africa, and the islands of the Pacific, all of which are situated in tropical or sub-tropical region, approximately 170 million people are suffering from this devastating parasitic disease. Although filariasis is infrequently fatal, it is the second principal cause of permanent and long-term disability in the world. Although difficult, but this disease is eradicable. Filariasis has been named by the World Health Organization (WHO) as one of only six potentially eradicable infectious diseases and the WHO has also undertaken a 20-year campaign to eradicate the disease. (Sasa, 1976) The disease is transmitted as follows: a mosquito first bites an infected individual then it bites an uninfected individual and thereby transfers some of the worm larvae to thebody of the uninfected person. After entering into the human body, the larvae move to a particular part of the body and then makes that part as their shelter and mature to adult worms. (Sasa, 1976). Filariasis can be classified into three different types on the basis of the part of the body that gets infected: (i) lymphatic filariasis: in this case the circulatory system that moves tissue fluid and immune cells, i.e. the lymphatic system gets affected; (ii) subcutaneous filariasis: in this case the areas below the skin and whites of the eye are infected; and (iii) serous cavity filariasis: in this case the larvae infect body cavities but do not cause disease. A number of different types of worms are held responsible for each type of filariasis, but the most common species which cayse the diseases include the following: Wucheria bancrofti, Brugia malayi (lymphatic filariasis), Onchocerca volvulus, Loa loa, Mansonella streptocerca, Dracunculus medinensis (subcutaneous filariasis), Mansonella pustans, and Mansonella ozzardi (serous cavity filariasis). The diseases are generally named after these worms, e.g. filariasis caused by Onchocerca volvulus is known as Onchocerciasis, diseases caused by Wucheria bancrofti and Brugia malayi are known as Bankcroftian and Malayan filariasis, respectively, and so on. Bancroftian and Malayan filariasis are the two most common types of the disease among all different kinds of filariasis. They are both forms of lymphatic filariasis. Africa, southern and southeastern Asia, the Pacific islands, and the tropical and subtropical regions of South America and the Caribbean are the main areas where the Bancroftian variety is generally found. Malayan filariasis is, however, found in limited areas, it occurs only in southern and southeastern Asia. Filariasis is also found in the United States, particularly among immigrants from the Caribbean and Pacific islands, but in U.S. it is found only occasionally. (Sasa, 1976; Ahorlu et al, 1999) A larva generally takes six months to one year to get matured into an adult worm. The adult worm then can live within the human body between four and six years. Each female worm has the ability to produce millions of larvae, and on of the most prominent feature of these larvae is that they only appear in the bloodstream at night, when they may be transmitted, through an insect bite, to another host. A single bite of a mosquito carrying larvae is, however, not enough to acquire an infection, therefore, short-term travelers in the areas of tropical and subtropical regions are usually safe. To create a serious infection in a human body a series of multiple bites over a long period of time is essential. Therefore, those individuals who work outdoors at night on a regular basis and those who spend a lot of time in remote jungle areas are usually at a very high risk of contracting the filariasis infection. (Sasa, 1976) Causes and symptoms of different type of filariasis: In the case of the most common form of the disease, lymphatic filariasis, the adult worms which live in the lymphatic vessels near the lymph nodes cause the disease. They distort the vessels and cause local inflammation. In advanced stages, the worms are quite able to obstruct the vessels, and they cause the surrounding tissue to become inflamed. In case of Bancroftian filariasis, the legs and genitals are the areas, which get affected, while the Malayan variety affects the legs below the knees. When inflammation takes place repetitively, it leads to blockages of the lymphatic system, particularly in the genitals and legs. As a result the infected area becomes grossly enlarged, with thickened, coarse skin. This consition is called elephantiasis. (Sasa, 1976) In case of conjunctiva filariasis, the worms larvae move to the eye and sometimes can also be seen moving beneath the skin or beneath the white part of the eye (conjunctiva). If it remains untreated, this disease can cause a type of blindness known as onchocerciasis. The symptoms of some specific and common forms of filariasis can be discussed in more detail.. Symptoms usually vary, depending on what type of parasitic worm has caused the infection, but most of the time all infection start with symptoms like chills, headache, and fever between three months and one year after the insect bite. There may also be swelling, redness, and pain in the arms, legs, or scrotum at the early stages. Symptoms of Onchocerciasis: Onchocerci volvulus causes the most serious clinical disease in the skin. They are most abundant in the skin but in some occasions also migrate to the eyes, lymph nodes, and other deep organs, where they create severe and progressive inflammatory lesions. In this case , the blackfly generally act as the vector and very often it’s bite leaves a bleeding point on the skin, with and severe itching. Multiple bites in a non-immune person produce pruritus, pain, and urticaria. (Rodger, 1977) Onchocercomas are basically subcutaneous nodules that contain adult worms. Nodules are very stiff, and often flattened or bean-shaped. These nodules can usually move, and they are also contender. Nodules are distributed in different ways in the various endemic areas. In Africa, it is the pelvis around which nodules are generally occurring. However, when infections become severe, these nodules develop over many other bony areas and in deeper sites. In Mexico and Guatemala, on the other hand, in most of the cases nodules are generally found to arise in the upper portion of the body, particularly the head. Usually, nodules are found to be close to each other and develop large masses containing small satellite nodules. This generally gives a shape and feel of tumor. (Rodger, 1977) Onchodermatitis, on the other hand, usually causes itching and it occurs mostly over the lower trunk, pelvis, buttocks, and thighs. Usually, it does not spread all over the body, and most of the time it is confined to one anatomic part of the body. Itching, and the consequent lesions caused by scratching, may be the only symptoms of mild infections. The scratching can be very dangerous; it can produce ulcers, bleeding, and secondary infections. At the stage of early infection, alterations in skin pigmentation can take place. During the early stages of infection, the clinical differential of the itchy rash includes scabies, contact dermatitis, insect bites, food allergies, and prickly heat. (Rodger, 1977) In Africa, a very chronic change takes place on the skin. At the primary stage, chronic lesions take place in the form of scaling, edema, depigmentation, and papule formation The edema is able to produce an effect called peau dorange with pitting around hair follicles and sebaceous glands. In the later stage, a number of things can happen, for example loss of elasticity, atrophy of the epidermis, and scarring of the dermis manifested in form of presbyderma for which skin gets an aged appearance with wrinkles , and the skin becomes typically extremely thin with little subcutaneous tissue. Apart from these, another thing that can also happen is persistence of epidermal tissue with hypertrophy and lichenification, which results first in elephantoid and ultimately in lizard skin. (Rodger, 1977) In the rain forests region of West Africa, one of the most striking and common symptoms of long-standing onchocerciasis is a characteristic leopard spot depigmentation over the skins. This is sometimes mistaken for leprosy, but the dissimilarity between the two lies in the fact that unlike lepromatous lesions, no sensory changes are present in case of this depigmentaion spot caused by onchocerciasis. (Rodger, 1977) In Latin America, however, chronic lesions are less common. In Latin America, different types of more acute skin lesions occur. Acute lesions, which occur rarely in Africa but frequently in Latin America, include the erisípela de la costa, which is basically a macular rash with edema of the face, and mal morado, which is a red-brown discoloration mainly, found on the trunk and upper limbs. (Rodger, 1977) Symptoms of Bancroftian and Malayan Filariasis: In case of Bancroftian and Malayan filariasis, the basic symptoms are related to damaged lymphatics. If Bancroftian and Malayan filariasis occurs, it causes severe structural and functional abnormalities of lymphatic channels even in entirely asymptomatic individuals with microfilaremia. Adult worms typically induce local reactions through a number of undefined mechanisms. These cause a number of abnormalities in lymphatic channels, e.g. dilatation and tortuosity of lymphatic vessels, hypertrophy of vessel walls, loss of valvular function, and backflow of lymph. In case of Bancroftian and Malayan Filariasis, bacteria aggravate the situation and promote the clinical manifestation of filarial infection. Wise and Minett in British Guiana first provided the earliest evidence of the role of bacteria in aggravating and promoting filarial infection in 1912. In 1932, OConnor provided some evidence, which suggested that living worms produced no serious pathological condition but that dead and dying worms can produce damaging effect by initiating an immunologic response that leads to clinical elephantiasis independent of any secondary bacterial infection. (Sasa, 1976; Ahorlu et al, 1999) Symtoms of Loiasis: In case of Loiasis, the patients may show the symptoms of chronic urticaria and Calabar swellings. When loiasis occurs sections of skin infrequently reveal microfilariae in dermal vessels and intermittently favor capillaries around sweat glands. In most of the cases a mild chronic focal inflammatory cell penetrate in the dermis and and there are also present fibrosis of dermal papillae. Exceptionally, in case of loiasis mild dermal eosinophilia is found to be present. Loiasis generally causes a characteristic localized lymphadenitis that is found incidentally. Other symptoms of Loiasis are diffuse edema of the hand or forearm, generalized rashes, fever, a feeling of irritation, confusion, and jacksonian epilepsy. Loiasis is also capable of causing orchitis, scrotitis, and swelling of the spermatic cord. A dead adult worm in the spermatic cord region can also produce a hydrocele. In case of loiasis, patients seldom develop nephropathy, cardiomyopathy, or damages in the pulmonary system like pulmonary infiltrates and pleural effusion. Acute arthritis with effusion is an uncommon complication, which is mainly developed when loiasis occurs. Some evidence suggests that loaiasis can also worsen psoriasis. (Sasa, 1976) Symptoms of Mansonelliasis: Mansonelliasis causes subcutaneous inflammation of the arms, shoulders, and face; acute pain in abdomen; pruritus; pleuritis; arthralgia; and fatigue. Worms, which can degenerate, produce inflammatory exudates, which contain eosinophils, neutrophils, plasma cells, and macrophages. All of these can be manifested as focal abscesses that can develop into granulomas and scars. (Sasa, 1976) Diagnosis of filariasis: Generally to diagnose filariasis patient history is taken, a physical examination is performed, and a screening of blood specimens for some particular proteins that are produced by the immune system in response to the infection is used to be done. In case of filariasis of any form diagnosis of the disease at the very early stage is quite difficult since in the initial stages of the disease, the symptoms of the disease are quite similar to the other bacterial skin infections. For making an accurate diagnosis, the physician generally looks for a pattern of inflammation and signs of lymphatic obstruction, together with the patients possible vulnerability to filariasis in an area where filariasis is used to be a common disease. The larvae, i.e. microfilariae can also be found in the blood, but because mosquitoes, which act as the vector of the disease, are active at night, the larvae are usually only found in the blood during night, especially between about 10 pm and 2 am. (Kesse, 1957) Presently a new form of diagnosis, called cytodiagnosis is attracting special attention. In the field of diagnosing filariasis, a special focus is being placed on cytodiagnosis. Several researches have been done to examine the effectiveness of cytology in diagnosing filariasis. Demonstration of microfilaremia, the specific test that is generally undertaken for diagnosing lymphatic filariasis, often gives false negative results in endemic areas. A group of researches conducted a study in an endemic area and they showed that microfilariae or adult worms of Wuchereria bancrofti were present in fine needle aspirates collected from a microfilariaemic cases. In a few cases the discovery was incidental. The researches took under consideration a total 4,534 cases undergoing cytologic evaluation and carefully screened all those cases for the presence of adult worms or larvae, irrespective of clinical diagnosis. Microfilariae were found to be present in both clinically suspected cases of filariasis and asymptomatic cases. (Mallick,et al, 2007)In this context a number of other studies can also be taken under consideration to draw a conclusion about the effectiveness of cytodiagnosis. For example, another group of researchers studied 6 cases of filariasis diagnosed by fine needle aspiration cytology. They found out that three of the cases showed symptoms of filariasis while the remaining three, which are associated with other disease, were asymptomatic. They declared that careful screening of FNAC (fine Needle Aspirates Cytology) smears might be helpful in detecting both symptomatic and asymptomatic patients. (Varghese, 1996) Another group of scientists studied two different cases in which FNAC smears showed sheathed microfilaria of Wuchereria bancrofti while peripheral blood smears, the common screening test of filariasis, failed to show the parasites and therefore the scientists stressed the value of routine fine needle aspiration cytology in the detection of filariasis and stated that the absence of the filarial parasite in the blood smear does not exclude filarial infection. (Sivakumar, 2007) To provide evidence for the effctiveness of cytodiagnosis another case can be taken where a endoscopic brush biopsy for a 54-year old male with epigastric irritation revealed filarial parasites even though patient did not present any symptoms suggestive of filariasis. The examination of gastric brushing can also be used to detect unexpected in addition to endoscopic biopsy. This is another case that proved the usefulness of cytology in the detection of Filariasis.( Singh, et al, 1999) Based on different studies, one can suggest that despite several sophisticated investigations towards the diagnosis of lymphatic filariasis without microfilaremia, there is still a cheap, simple and easy method of fine needle aspiration cytology, which may have an impact. However further studies are required before making any claims. (Mallick,et al, 2007) Treatment: The medicines, which are commonly used to treat filariasis infection, include ivermectin, albendazole, and diethylcarbamazine. These medicines helped in eliminating the larvae, impairing the reproductive ability of the adult worms, and actually killing adult worms. It is, however, very unfortunate that much of the tissue damage caused by filarial infection may not be reversible. The medication is usually started with mild doses to prevent reactions that can be caused by the death of parasites in large numbers. Very often the medications are found to be effective but it can also cause severe side effects in up to 70% of patients as a result either of the drug itself or the massive death of parasites in the blood. Diethylcarbamazine, for example, can cause severe allergic reactions and the formation of pus-filled sores or abscesses. These kind of side effects can, however, be mitigated by giving the appropriate dose of antihistamines and anti-inflammatory drugs simultaneously with the drugs that are given for the treatment of the main disease. In rare occasions, treatment with diethylcarbamazine in someone with very high levels of parasite infection may also lead to a fatal inflammation of the brain (encephalitis). In this case, the fever is followed by headache and confusion, then stupor and coma caused when massive numbers of larvae and parasites die. Other common side effects include vertigo, weakness, and queasiness. Therefore, various types of symptoms caused by the death of the parasites during the medication period include fever, headache, muscle pain, pain in abdominal area, queasiness and vomiting, weakness, dizziness, tiredness, asthma etc. Reactions usually begin within two days of starting treatment and generally last between two and four days. (Kessel, 1957) In case of elephantiasis no treatment can reverse it. In this case, surgery can be done to eliminate surplus tissue and make a way through which the fluid around the damaged lymphatic vessels can be drained away. Surgery may also be used to ease massive enlargement of the scrotum. Elevating the legs and providing support with elastic bandages can also help elephantiasis of the legs. (Kessel, 1957) Prevention: Everybody knows that prevention is always better than cure. So it would be a very wise step if people place serious focus on the prevention of the disease. The best way of preventing filariasis is to prevent being bitten repetitively by the mosquitoes, which are the vectors of the disease. Some preventive measures can be as follows: Restricting outdoor activities at night, particularly in rural or jungle areas, since mosquitoes generally bite in the night and jungle are filled with mosquitoes, During outdoor activities, particularly at night, wearing long sleeves and pants and avoiding dark-colored clothing that attracts mosquitoes, Avoiding perfumes since it attracts the insects, Wearing some insect repellent or, particularly for children, trying citronella or lemon eucalyptus, to keep away insects from the body. If one has to sleep in an open area or in a room with poor screens, using a bed net to avoid being bitten while asleep. Using air conditioning as the cooler air makes insects less active. (Kessel, 1957) Conclusion: Filariasis, being a mysterious disease, proper care should be taken to keep away from this disease. Although it is not fatal, it makes life miserable. It brings about drastic changes in normal way of living. Since treatement of filariasis produce a number of side effects, it would be better to take some preventive measures as mentioned above so that it can’t ruin lives. Filariasis can be controlled effectively in highly infected areas, particularly in tropical and subtropical regions, by taking ivermectin preventatively before being bitten. Currently, there is no preventative vaccine available for filariasis, but scientists are working on a preventative vaccine at this time. References 1. Ahorlu CK, Dunyo SK, Koram KA, Nkrumah FK, Aagaard-Hansen J, Simonsen PE.(1999). Lymphatic filariasis related perceptions and practices on the coast of Ghana: Implication for prevention and control. Acta Tropica 73: 251-264, 2. Amuyunzu M. Community perception regarding chronic filarial swellings: a case study of the Duruma of coastal Kenya. East African Medical Journal 74(7):411-5, 1997. 3. Kessel J.F. (1957). Disabling effects and control of filariasis. American Journal of Tropical Medicine and Hygiene 6: 402-414, 4. Varghese R.T., Raghuveer, C.V.,. Pai, M.R., and Bansal, R. (1996). Mirofilariae in Cytologic Smears: A Report of Six Cases. Acta Cytologica, 40, 299-301 5. Sivakumar, S. (2007). Role of Fine Needle Aspiration Cytology in Detection of Microfilariae: Report of 2 Cases. Acta Cytologica, 51, 803-806. 6. Ahluwalia C., Bajaj P. (2003). Incidental detection of microfilariae in aspirates from Ewing’s sarcoma of bone. Diagn Cytopathol., 29(1), 31- 2. 7. Singh, M., Mehrotra, R., Shukla, J. and Nigam, D.K. (1999). Diagnosis of Microfilaria in Gastric Brush Cytology: A Case Report. Acta Cytologica, 43, 853-855. 8. Sasa, M. (1976). Human filariasis: a global survey of epidemiology and control, Baltimore: University Park Press. 9. Rodger, F.D. (1977). Onchocerciasis in Zaire: A New Approach to the Problem of River Blindness. Oxford: Pergamon Press. 10. Mallick, M.G., Sengupta, S., Bandyopadhyay, A., Chakraborty, J., Ray, S. and  Guha, D. (2007). Cytodiagnosis of Filarial Infections from an Endemic Area. Acta Cytol. 51: 843–849 Read More