(M) Nematoda: Filarial Worms (Module-based) Flashcards
referred as blood and tissue-inhabiting nematodes, live in the tissues and/or body cavities of a vertebrate host including man
Filarial worms
(male/female worm) larviparous and insect vectors are needed for transmission of the infection
Female worms
The laid larvae are called?
microfilariae
The time of the day whereby blood and other tissue fluids contains abundant number of microfilariae, as compared to other hours, is called
which is of great value in the timing of when to get clinical specimen to produce high yield of positive results
periodicity
known to be an endosymbiont of filarial worms, including W. bancrofti, B. malayi and O. volvulus
Wolbachia bacteria
This is sucked by the insect vector, pass through the gut’s wall and into the hemocele of the insect.
microfilariae
What stage goes into some parts of the vector’s mouth or salivary glands.
3rd stage filiform larva (L3)
causative agent of Bancroftian’s filariasis
Wuchereriabancrofti
It is highly endemic in Amoean Ellice, Tokelau, and Fiji Islands.
Wuchereria bancrofti
It is also found in Burma, India, Saudi Arabia, Mauritius, Egypt, West and East Africa, and Congo.
Wuchecheria bancrofti
Males: 40mm long x 0.1mm in diameter with sharply curved posterior.
Females: 80-100mm x 0.24-0.30mm with vulva at cervical region, single
uterus, but all the remaining reproductive organs are paired.
Microfilaria: 244-296um long x 7.5-10um in diameter, sheathed, with graceful curves, rounded anterior, pointed caudal part, smooth cuticle, and body
nuclei are equidistant and regularly distributed.
Wuchecheria bancrofti
causes Malayan filariasis
BRUGIA MALAYI
It is endemic in India, Sri Lanka, Sumatra, Java, Borneo, Celebes, Malaysia, the Philippines, Thailand, North Vietnam, China, South Korea, and Japan.
Brugia malayi
causing Calabar or Fugitive swelling involves the eyes with microfilariae that exhibit diurnal periodicity
Loa loa
Endemic in west and Central Africa, especially Nigeria, Cameroon, and Zaire, and vectors are species of tabanid flies of genus Chrysops.
Loa loa
vectors of W. bancrofti & B. malayi
Mansonia
Aedes
Anopheles
Cules
Females measure 43-55mm long, 130-170um (diameter)
Males 13-23mm long x 70-80um in breadth
Microfilaria 177-230um, sheathed, with a kinky body, unevenly distributed
body nuclei, two prominent terminal nuclei which is diagnostic.
BRUGIA MALAYI
Vectors of Loa loa
Sp. of tabanid flies of genus Chrysops
Adult worm inhabiting subcutaneous tissues have a pair of lateral papillae and two pairs of sub-median papillae, all of which are sessile and are small. The skin has small bosses, which are not seen in males.
Loa loa
Male: measure 30-34 mm long by 0.35-0.43 mm in diameter
Females: 40-70 mm by 0.5 mm
Microfilaria: measures 250-300 x 6-8um with uneven distribution of body
nuclei that extend to the tip of the tail.
Loa loa
producing onchocerciasis or river blindness, with microfilariae in lymphatic fluids and both adults and microfilariae may be found in the skin and subcutaneous tissues where they produce fibrous nodules.
Onchocerca volvulus
Onchocerca volvulus commonly known as
Convoluted filaria
Vectors of Onchocerca volvulus
Black flies of genus simulium
Adult worms are white, opalescent, and transparent, with distinct transverse striations of the cuticle. Males are 19-24mm long x 130-210um in diameter. Females are 3.5-50mm x 270-400um in diameter. Microfilariae are 315-360um by 6um with both ends free of nuclei.
Onchocerca volvulus
Onchocerca volvulus may be found in what specimens?
Urine, blood and sputum
Onchocerca volvulus are commonly found in what areas/tissues of the body?
more commonly in the lymphatic of the connective tissues and cutaneous layers in an area around the adult worms in the corneal conjunctivae.
with adults inhabiting in body cavities, producing non- periodic, unsheathed microfilariae
Mansonella ozzardi
Mansonella ozzardi AKA
Ozzard’s filaria
They ca be found in Argentina, Bolivia, Brazil, Peru, Venezuela, Trinidad, Colombia, and Panama. Insect vectors are midges of genus Cullicoides.
MANSONELLA OZZARDI
Adult male measures 24-28mm long by 70-80um diameter. Females are 65- 81mm long by 0.21-0.25mm diameter. The microfilariae measures 200um by 4.5um. The tail end is tapered like a filament, contains a column of four to six ovoid or bar-like body nuclei.
Mansonella ozzardi
Mansonella perstans is also called
Dipetalonema perstans
Adult worms inhabit the body cavities in man. It is non-periodic, and unsheathed microfilariae. They are native in in South America and Africa. Vectors are midges of genus Cullicoides.
Mansonella perstans
Adult male measures 45mm long x 60um. Females are70-80mm long x 120um. Microfilariae measures 200um x 4.5. The body nuclei fill up entire body,
with no distinct space at cephalic or tail end.
Mansonella perstans
TOF. The microfilariae are the ones causing damage to humans and dependent on where the worm is located.
F (adult worms)
Adult worms, in body cavities and subcutaneous tissues, produce what swelling?
nodular swelling
Adult worms, in body cavities and subcutaneous tissues, produce nodular swelling such as those found in infections with?
Mansonella perstans
Migrating adults of L .loa cause temporary migratory inflammation, thus the term?
Fugitive or calabar swelling
Swelling in the eyes is also called
bug, bung, or bulge eye
Sp.
usually produces little tissue reactions and are commonly not observed
Mansonella ozzardi
This parasites are commonly located in lymphatic channels of the subcutaneous tissues in areas with bony prominence such as the scalp, scapula, ribs, elbow, iliac crests, sacrum, and knees.
Onchocerca volvulus
oftentimes, located in lymphatic channels of the lower part of the body
Wuchecheria bancrofti & Brugia malayi
This incite cellular reaction in lymph nodes and lymphatic channels.
ADULT WORMS
These changes, running a gradual course, eventually lead to lymphatic obstruction causing impedance in the flow of lymph, which in chronic cases lead to?
Lymphedema (enlargament of the involved extremities)
Enlarged lower extremities, due to lymphedema, assume the appearance of an elephant’s legs, hence the term?
Elephantiasis
may cause lymphangitis, lymphadenitis, orchitis, epididymitis, funiculitis, elephantoid fever, secondary bacterial infection, dilatation of lymphatics with hypertrophy and hyperplasia, progressive obstruction of the lymphatic channels due to scar tissue formation ending with fibrosis, lymph blockade, and finally elephantiasis of the affected organ or limb.
Bancroft’s or Malayan filariasis
periodic type is generally distributed throughout Asia
Nocturnal
periodic type is found to be limited in some areas of Malaysia, Indonesia, and the Philippines (Bicol); has animal reservoir hosts, such as domestic cats, leaf monkeys, and other wild animals.
Nocturnal subperiodic
Bancroft’s filariasis
as main vector (urban type) and is found in almost the whole tropical and subtropical regions
Culex quinquifasciatus
Bancroft’s filariasis
rural form serve as vectors and can be found in the Philippines.
Anopheles maculatus, A. flavirostris, and Aedes poicilus
Manifestations of Bancroft’s filariasis are the same with those seen in Malayan filariasis, but W. bancrofti affects?
genital organs more than Brugia malayi
Cases of hydrocele, orchitis, funiculo-epididymitis, chyluria are more commonly observed in what disease/parasite
Wuchercheria bancroft or bancroft’s filariasis
Lab diagnosis to demonstrate adult worms
Lymph node or tissue biopsy may be done, stained with Haematoxylin-Eosin method
Laboratory Diagnosis of filaria worm infection is based on recovery of microfilariae in?
blood films or lymphatic fluids
TOF. When most of the clinical signs/symptoms are prominent, it is the time when the microfilariae tend to be very few in the blood.
T
TOF. During the sub-clinical period, the blood is oftentimes free of organisms.
T
Treatment
both kill the microfilariae and adult worms is the drug of choice for lymphatic filariasis
Diethylcarbamazine citrate (DEC)
Treatment
This medic. is effective against the microfilariae of W. bancrofti only, not the adult worm.
Ivermectin
Treatment
Ivermectin is effective against the microfilariae of?
W. bancrofti only
TOF. Ivermectin is effective against the adult worm of W. bancrofti only.
F (microfilaria)
Control and Prevention
- Public education, especially those at risk of the infection, and early diagnosis and immediate treatment, which in turn control transmission to vectors will markedly reduce incidence of the infection
- Use of insect repellants, mosquito nets, changing the nature of the mosquitoes’ breeding places will greatly lower the incidence of infection
