Wuchereria exhibits nocturnal periodicity because the microfilarial release by Wuchereria are according to the circadian rhythm in which the pathogen is less active in daytime as compared to night so they are not able to penetrate capillaries during daytime and this phenomenon is considered as nocturnal periodicity.
Why there is nocturnal periodicity of microfilariae?
It is universally accepted that the periodicity of microfilariae, or the circadian rhythm of microfilariae, is due to the periodic migration of microfilariae between the peripheral blood and the lung capillaries, that is, in the case of Wuchereria bancrofti in Japan, micro- filariae were found in the finger-prick blood ...
Is Wuchereria bancrofti nocturnal periodicity?
Background & objectives: Wuchereria bancrofti has shown nocturnal periodicity in India and other endemic countries of the world except pacific regions where non-periodic or diurnal sub-periodic forms have been reported. Presence of sub-periodic form of W.
Why is there nocturnal periodicity?
Nocturnal periodicity is the circadian rhythm with a primary expression of periodicity. It occurs during the night and the release or movement of the parasite into the peripheral blood. This character is exhibited by Microfilaria. Wuchereria bancrofti larvae called microfilariae show nocturnal periodicity.
Is Wuchereria nocturnal?
Adults produce microfilariae measuring 244 to 296 μm by 7.5 to 10 μm, which are sheathed and have nocturnal periodicity, except the South Pacific microfilariae which have the absence of marked periodicity.
Is Wuchereria bancrofti diurnal?
In the Caribbean area, South America, Asia, East and West Africa, and Papua New Guinea, the microfilariae of this worm exhibit nocturnal periodicity; in the South Pacific, their periodicity is diurnal. W.
What is the importance of Microfilarial periodicity?
The behaviour of microfilariae is adapted to promote transmission by arranging the maximum number of microfilariae in the peripheral blood at times when the arthropod vector is likely to bite. The most sophisticated arrangement to achieve this is by a 24 h rhythm—the classical 'periodicity'.
Which larva of parasite has nocturnal periodicity?
Wuchereria bancrofti, Brugia malayi and B. timori produce microfilariae that usually appear in the blood between 2200 and 0200 hours (nocturnal periodicity).
Which one of the following has nocturnal periodicity?
Thus, the correct answer is 'Microfilaria'.
What is meant by nocturnal periodicity with reference to the life history of a nematode parasite you have studied?
Solution : The microfilaria larvae of wuchereria Bancroft in man move in the peripheral blood circulation during the night time between 10 pm and 4 am. This tendency is referred to as nocturnal periodicity.
What is meant by Microfilarial periodicity?
The periodicity of microfilariae is a mechanism by which a compromise is arranged between the two requirements of the microfilariae (optimum survival and transmission).
What is microfilaria of Wuchereria bancrofti?
The microfilariae of Wuchereria bancrofti are sheathed and measure 240—300 µm in stained blood smears and 275—320 µm in 2% formalin. They have a gently curved body, and a tail that is tapered to a point.
What is the characteristics of Wuchereria bancrofti?
CHARACTERISTICS: Wuchereria bancrofti is a filarial nematode that, as an adult, is a thread-like worm(1,2,3). The female nematodes are 10 cm long and 0.2 mm wide, while the males are only about 4 cm long(1,3).
Which parasite has nocturnal periodicity?
The microfilariae that cause lymphatic filariasis circulate in the blood at night (called nocturnal periodicity).
What is the periodicity of microfilariae?
The periodicity of microfilariae is a mechanism by which a compromise is arranged between the two requirements of the microfilariae (optimum survival and transmission).
At what time does w Bancrofti appear in the peripheral blood stream?
Wuchereria bancrofti and the Brugia species exhibit nocturnal periodicity, and the optimum time for blood collection is between 10:00 p.m. and 2:00 a.m. (1), although there is a subperiodic strain of W. bancrofti in the South Pacific whose peak times are between 12:00 p.m. and 6:00 p.m. (6).
What is the characteristics of Wuchereria bancrofti?
CHARACTERISTICS: Wuchereria bancrofti is a filarial nematode that, as an adult, is a thread-like worm(1,2,3). The female nematodes are 10 cm long and 0.2 mm wide, while the males are only about 4 cm long(1,3).
Where does Wuchereria bancrofti affect?
Wuchereria bancrofti affects patients in equatorial Africa, India, the Mediterranean coast, the Caribbean, coastal areas of South America, and parts of Central America;
How many stages of life are there in Wuchereria Bancrofti?
Wuchereria bancrofti, B. malayi and B. timori have five morphologically distinct stages of their lifecycle ( Fig. 110.2). The first stage larvae or microfilariae are released from fecund adult female worms that release up to 10,000 microfilariae per day, which circulate in the blood. Microfilariae are approximately 250 µm long and 10 µm wide and have an acellular sheath. Microfilariae of W. bancrofti and B. malayi differ morphologically based on the pattern of nuclei in the caudal and cephalic regions. Microfilariae are most abundant in the circulation at night (nocturnal periodicity), and during the day the microfilariae sequester in the deep vascular beds. This periodicity is thought to prolong the survival of microfilariae (~9 months) and result in high levels of microfilaria in some individuals (e.g. >10,000/ml).
What are the two types of worms that cause tropical pulmonary eosinophilia?
Two filarial worms that naturally infect humans and cause tropical pulmonary eosinophilia (TPE) are considered here, Wuchereria bancrofti and Brugia malayi , the causes of bancroftian and brugian filariasis, respectively. The adult filarial worms of these genera do not usually cause lesions in the lungs, but occasionally become lost during migration and may be found in the lungs. Similarly, more rarely encountered animal filarial worms may occasionally be found in human tissues (e.g., zoonotic Brugia species).
What are the characteristics of W. bancrofti and Brugia species?
An important characteristic of W. bancrofti and Brugia species is the presence of an obligate intracellular bacterial endosymbiont, Wolbachia. Wolbachia parasites support essential biochemical pathways necessary for the parasite survival especially for embryogenesis and molting that is critical for transition from one parasite stage to another [10, 11].
Why are filarial worms absent from blood smears?
This is because the microfilariae released by the adult filarial worm are rapidly cleared by the lung and other organs, such as the spleen.
How wide are microfilariae?
Microfilariae are approximately 250 µm long and 10 µm wide and have an acellular sheath. Microfilariae of W. bancrofti and B. malayi differ morphologically based on the pattern of nuclei in the caudal and cephalic regions. Microfilariae are most abundant in the circulation at night (nocturnal periodicity), and during the day ...
Why do filarial worms require surgical excision?
An adult filarial worm that has aberrantly migrated to the lung produces patchy or well-circumscribed pulmonary lesions that prompt surgical excision because of the possibility of malignancy