Lymphatic chronic filariasis is the main cause of elephantiasis due to occlusion of lymphatic vessels by the worms. It causes disfiguring of the affected part of the body due to edema and skin thickening. The Culex mosquito, the Anopheles and the Aedes mosquito are the vectors carrying the parasites at specific stages of their development. Elephantiasis causes peripheral edema of the upper limbs and the lower limbs. Filariasis infection mainly affects the lymphatic system. It plays a major role in regulating tissue pressure, regulating the immune system and absorption of dietary fat in the intestines. Lymphatic vessels carry lymph from the interstitial spaces. The spleen together with other lymph nodes produces white blood cell that protect the body from bacteria. According to Mohan, Bisht, Goel & Garg (2012) women have a reduced incidence of filarial infection as compared to men. However, due to the chance of developing vulva filariasis, the complications are often worse than those in men.
Patients suffering from filariasis present with symptoms such as elephantiasis and lymphedema (Mendoza, Li, Gill & Tyring, 2009). According to Tada (2011) elephantiasis occurs or happens in advanced stages of lymphatic filariasis. The stages of larval development should be well understood to explore how the disease manifests itself. According to Tada (2011) the larval in their third stage of development grow to maturity inside the lymphatic system. This mainly occurs in the genitourinary system. Yimer, Hailu, Mulu & Abera (2015) argued that elephantiasis is manifests itself with chronic lymphangitis and presence of parasitic worms in blood and lymph. Ultrasonography can be used to identify the worms moving actively inside the lymphatic system. As blockage of the lymph vessels progress, the patient encounters lymphedema of the legs, mammae, arms and other peripheral areas. Tada (2011) noted that the connective tissues of the subcutis are the ones mainly affected by hyperplasia which is experienced in this stage.
Parasites causing lymphatic filariasis are nematodes of the family Filaridae. They are classified into three types which include Wuchereria bancrofti, Brugiamalayi and Brugiatimori. Wuchereria bancrofti causes 90% of the elephantiasis cases. This affects the normal functioning of the lymphatic system. When mosquitoes bite an infected host, they get infected by the microfilariae. Microfilarie mature into infective larvae inside the mosquito and are deposited to another host after a mosquito bite. Inside the new host they travel to the lymphatic vessels and mature into worms hence continuity of their life cycle and the transmission cycle.Maturity of third stage larvae occurs in the lymphatic vessels in the genital-urinary system leading to blockage of the lymphatic vessels.Maturity of third stage larvae occurs in the lymphatic vessels in the genital-urinary system leading to blockage of the lymphatic vessels. Although most of the elephantiasis infections are asymptomatic, they still cause damage to the lymphatic system, the immune system and the kidneys. Skin thickening, also known as elephantiasis is the most common presentation in lymphatic filariasis. Other external signs include lymphedema and hydrocele. In the chronic stages, the urine of the infected person is milky (chyluria) and they sometimes presnt with hemato-chyluria which is chyluria contaminated with blood. Elephantiasis may have been in existence since 200 BC. Documentation of lymphatic filariasis began between 1588 and 1592.
Parasite Life Cyle
Shenoy (2008) argued that lymphatic filariasis which is transmitted by mosquitoes isthe commonest cause of the disease in tropical countries. There are several stages important in the microorganism’s life cycle. The larva develops to the infective stage inside the mosquitoes. The larval stage of the infective microorganism is transmitted to humans through mosquito bites. These larvas enter the lymphatics where they develop. As they develop, the lymph vessels dilate due to increasing size of the larva. The damage caused by the larva is thought to be irreversible. The lymphatic damage exposes the affected person to other types of infection such as bacterial ones due to the compromised lymph system due to blockage. According to Shenoy (2008) the patient experiences recurring acute attacks of demato-lymphangio-adenitis either in the lower or upper limb. The human and the mosquito therefore serve as the only hosts for the parasite. Sgenoy (2008) noted that elephantiasis manifests in the late stages of lymphatic filariasis.
Several risk factors have been identified in the spread of the disease. The tropical and subtropical areas where mosquito is common have been identified as endemic areas predisposing individuals to the disease. This is determined by presence of the mosquito species transmitting the parasites. The parasites can only complete their life cycle in humans. Living in unhygienic areas and conditions has also been identified among the risk factors for the disease. The three roundworms are common in Africa, South East Asia, South America and India. If a person visits these areas and later presents with the symptoms highlighted below, it is important to consider an elephantiasis diagnosis.
Signs and Symptoms
The disease only shows symptoms in its advanced stages. The affected person will report swollen genitals, legs, breasts and arms. According to Molyrieux (2003) the three parasitic worms including Wuchereria bancrofti, Brugia malayi and Brugia timori can cause the disease with the manifestation of the symptoms being similar. Furthermore, the parasites’ lifecycle is the same. The damage of the lymphatic system leads to an impaired immune system. The impaired immune system is as a result of the blocked lymph vessels. The skin also becomes so thick, ulcerated and dry due to bacterial infections. The patient also presents with recurring chills and fevers.
The Center for Disease Control and Prevention provides a guideline that can be used in the diagnosis of microfilariae. The standard method is acceptable across the medical field since it focuses at identifying the microfilariae which are the elements which block lymphatic vessels leading to the symptoms explored. The microfilariae can be identified in the blood. The term ‘nocturnal periodicity’ is used to describe the behavior of the microfilariae where they migrate from the lympahtics and circulate in the blood and night. During this time, it is possible to run a smear and identify the small worms. Due to the behavior of the microfilariae, blood collection should be done at night. If done during the day, there are high chances that the physician will miss out on the presence of the microfilariae in the blood. According to the CDC guidelines for diagnosis, a thick smear should be made and stained with Giemsa or H & E. Concetration techniques are also widely accepted in the diagnosis to enhance the results. According to Shenoy (2011) nigh blood examination may also be used to detect mf. The Immuno-chromatographic-card test (ICT) card test is used for filarial antigenemia while ultrasonography is used to locate the worms are they circulate in the lymphatic system. The conduction of the tests should be done once the symptoms start presenting and the doctor is suspecting the presence of the worms. In differential diagnosis, Shenoy (2011) argued that there are other diseases which manifest with similar symptoms. Surgical processes may be needed to confirm the presence of the worms in the lymphatics. Lympatic imaging is also used in the differential stage due to the accuracy of results reported.
According to Shenoy (2011) the drug of choice for a long time has been Diethylcarbamazine (DEC). The management plan is put in place for the three parasite species. The microfilaricidal agent is totally destroyed by DEC. However, when the worms are already mature, DEC may not be as effective. It can only kill 50% of the worms. W. bancrofti, B. malayi, and B. timori reports similar effects with DEC management. For adults, 6mg/kg TDS is recommended. There are several complications which should be explored in the management phase. As the disease progresses, the affected person may present with reduced motor skills due to lyphedema of the peripheral regions. The lower limbs are often affected to a point that the person may not be able to complete the tasks they would have completed with ease before infection.
Elephantiasis is a common infection in tropical countries. The three worm species responsible for filariasis are spread by mosquitoes. The presence of mosquitoes in tropical countries explains the epidemiology of the disease in Africa, India and South America. The word ‘elephantiasis’ is derived from the symptom of the disease where the skin thickens resembling that of an elephant. The three worms, Wuchereria bancrofti, Brugia malayi and Brugia timori, enter the lymphatic system where they cause blockage. The reported symptoms are due to the blockage and compromised immunity after interfering with the immune system. Although elephantiasis can rarely cause death, it predisposes individuals to infections due to their compromised immune system. Death can be due to the opportunistic infections.