wuchereria bencrofti
TRANSCRIPT
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
WUCHERERIA BANCROFTI
ASIF IBRAHIM
By
LECTURER OF ZOOLOGYGOVT.DEGREE COLLEGE RAMBAN (J&K)
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
INTRODUCTIONWuchereria bancrofti is a human parasitic roundworm that is the major cause of lymphatic filariasis., that infect the lymphatic system to cause lymphatic filariasis. Filarial worms are spread by a variety of mosquito vector species. W. bancroftiis the most prevalent and affects over 120 million people, primarily in Central Africa and the Nile delta, South and Central America, the tropical regions of Asia including southern China, and the Pacific islands. If left untreated, the infection can develop into a chronic disease called elephantiasis. In rare conditions it also causes tropical eosinophilia, an asthmatic disease. Limited treatment modalities exist and no vaccines have been developed.
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
MORPHOLOGYAs a dioecious worm, W. bancrofti exhibits sexual dimorphism. The adult worm is long, cylindrical, slender, and smooth with rounded ends. It is white in colour and almost transparent. The body is quite delicate making it difficult to remove from tissues. It has a short cephalic or head region connected to the main body by a short neck which appears as a constriction. There are dark spots which are dispersed nuclei throughout the body cavity, with no nuclei at the tail tip. Male and female can be differentiated by size and structure of tail tip.
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
SIZE The male worm is smaller, 40 millimetres (1.6 in) long and 100 micrometres
(0.0039 in) wide, and features a ventrally curved tail. The tip of the tail has 15 pairs of minute caudal papillae, the sensory organs. The anal region is an elaborate structure consisting of 12 pairs of papillae, of which 8 are in front and 4 are behind the anus.
In contrast, the female is 60 millimetres (2.4 in) to 100 millimetres (3.9 in) long and 300 micrometres (0.012 in) wide, nearly three times larger in diameter than the male. Its tail gradually tapers and rounded at the tip. There are no additional sensory structures. Its vulva lies towards the anterior region, about 0.25 mm from the head. Adult male and female are most often coiled together and are difficult to separate. Females are ovoviviparous and can produce thousands of juveniles known as microfilariae
The microfilaria is a miniature adult and retains the egg membrane as a sheath, and is often considered an advanced embryo. It measures 280 μm long and 25 μm wide. It appears quite structureless 'in vivo', but histological staining makes its primitive gut, nerve ring and muscles apparent
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
HOSTS ( W.BENCROFTI)
W. bancrofti carry out their life cycle in two hosts. Human beings serve as the definitive host and mosquitoes as their intermediate hosts. The adult parasites reside in the lymphatics of the human host.
They are found mostly in the afferent lymphatic channels of the lymph glands in the lower part of the body. The first-stage larvae, known as microfilariae, are present in the circulation.
The microfilariae are found mainly in the peripheral blood and can be found at peak amounts from 10 p.m. to 4 a.m. They migrate between the deep and the peripheral circulation exhibiting unique diurnal periodicity. During the day, they are present in the deep veins, and during the night, they migrate to the peripheral circulation. The cause of this periodicity remains unknown,
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
The microfilariae are transferred into a vector, which are most commonly mosquito species of the genera Culex, Anopheles, Mansonia, and Aedes. Inside the mosquito, the microfilariae mature into motile larvae called juveniles. When the infected mosquito has its next blood meal, W. bancrofti is egested via the mosquito’s proboscis into the blood stream of the new human host. The larvae move through the lymphatic system to regional lymph nodes, predominantly in the legs and genital area. The larvae develop into adult worms over the course of a year, and reach sexual maturity in the afferent lymphatic vessels. After mating, the adult female worm can produce thousands of microfilariae that migrate into the bloodstream. A mosquito vector can bite the infected human host, ingest the microfilariae, and thus repeat the life cycle
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
LIFE CYCLE (W. BENCROFTI)
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
PATHOGENESIS The pathogenesis of W. bancrofti infection is dependent on the immune system and
inflammatory responses of the host. After infection, the worms will mature within 6–8 months, male and female worms will mate and then release the microfilariae. These microfilariae can be released for up to ten years
The asymptomatic phase usually consists of high microfilaremia infection In the inflammatory (acute) phase, the antigens from the female adult worms elicit
inflammatory responses. The worms in the lymph channels disrupt the flow of the lymph, causing lymphedema. The individual will exhibit fever, chills, skin infections, painful lymph nodes, and tender skin of the lymphedematous extremity.
The obstructive (chronic) phase is marked by lymph varices, lymph scrotum, hydrocele, chyluria (lymph in urine), and elephantiasis. Microfilariae are not normally present in this phase.
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
ELEPHANTIASIS
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
CONTROL
Prevention focuses on protecting against mosquito bites in endemic regions. Insect repellents and mosquito nets are useful to protect against mosquito bites. Public education efforts must also be made within the endemic areas of the world to successfully lower the prevalence of W. bancrofti infections.
1 MAY 2023AASIF IBRAHIM786@GMAIL .COM / AS IFKANTH89@GMAIL .COM
[email protected]@gmail.comMob.9070262786 / 9018533143