CN3 Filarial Worms Flashcards
What are creamy white, long, and filiform in shape?
Adult Wuchereria worms
Which Wuchereria worm is larger, male or female?
Female (8-10cm)
Bcs male is 2-4cm only
Where are adult male and female W. bancrofti worms found?
- Tightly and coiled in nodular dilatations in lymph vessels
* Sinuses of lymph glands
What gains entrance to the peripheral circulation where they are picked up by the vector?
Microfilariae - adult female filarial worm produces
What measures 270-290um and is enclosed in a hyaline sheath which is much longer than the microfilaria itself?
Wuchereria bancrofti
What measures 13-23 mm in length and 43-55 mm?
13-23 mm - male brugia
43-55 mm - female brugia
What is the mean length of Brugia malayi?
222um
What is the difference between the cephalic space or the breadth bread of W. bancrofti and B. malayi?
W. bancrofti 1:1
B. malayi 2:1
When the sheath is stain in gemsia what color will they produce?
W. bancrofti - unstained
B. malayi - pink
What has a single row of nuclei that does not reach the tail’s end?
Wuchereria bancrofti
It has two nuclei which bulge the cuticle and it is conspicuously placed
B. malayi
Does W. bancrofti have a terminal nuclei?
Nada
Innenkôrper length of W. bancrofti and B. malayi
W. bancrofti - 34um
B. malayi - 30.7um
LC of W. bancrofti and B. malayi as to its Mosquito Phase
On arrival in a blood meal in the stomach of an appropriate host, the microfilariae lose the sheath in the first how many hours?
2-6 hrs
LC of W. bancrofti and B. malayi as to its Mosquito Phase
Some of them work their way by use of hook at the cephalic end of the body through the wall of the proventriculous and cardiac portion of the midgut and then the course of how many hours?
4-7 hours have reached the thoracic muscles
LC of W. bancrofti and B. malayi as to its Mosquito Phase
During the next two days they metamorphose into what?
Short sausage shaped organism
LC of W. bancrofti and B. malayi as to its Mosquito Phase
What is the measurement of the short sausage shaped organism?
124-250 in length by 10-17um diameter
LC of W. bancrofti and B. malayi as to its Mosquito Phase
By the fifth or sixth day, the taoo has atrophied to a mere stump, the intestinal tract has become well-differentiated and a body cavity has developed although the genital primordial is what?
Still inconspicuous
Meanwhile the first true sheath has been shed
LC of W. bancrofti and B. malayi as to its Mosquito Phase
After the shed the larvae now measures 225-300 by 15-30 um and how many subterminal caudal papillae?
3 subterminal caudal papillae
LC of W. bancrofti and B. malayi as to its Mosquito Phase
During the early part of the second week, a second ecdysis occurs and the worms rapidly elongate into the what?
Filiform (3rd stage) mature larva
- 1.4-2mm by 18-23um
LC of W. bancrofti and B. malayi as to its Development in Human Host
The microfilariae discharged by the mature females may be expected to appear in the peripheral blood and how many months?
8-12 mos
Can filariasis without microfilaremia happen?
Yuh
LC of W. bancrofti and B. malayi as to its Development in Human Host
The adult worms in infected individuals are coiled up in nodal dilatations of the lymphatic vessels and most frequently where?
- In the cortex of the LN
- In the testicular tissues
What is the only known natural definitive host of w bancrofti?
Man
LC of W. bancrofti and B. malayi as to its Development in Human Host sequence
Blood meal –> Rupture of Mosquito’s proboscis –> Escape of Mature Larva –> Inoculation of the Human Host
In the bicol region what is more frequently encountered?
Hydrocoeles
What is the most widespread lymphatic filarial parasite?
W. bancrofti
What is the principal vector for malaria in the philippines and is also the vector for in the mount province, sulu, and palawan?
Anopheles minimus var. flavirostris
What breeds in water accumulated in the axils of abaca and banana plants and is the mosquito vector in other provinces?
Aedes poecilus
What mosquito vectors breeds in freshwater swamps?
Mansonia bonnae
What mosquito vectors breeds in rice fields?
Mansonia uniformis
What are important reservoir hosts that may transmit infection to humans?
Cats by cat-mosquito-man cycle
Animals show direct evidence that infection with bravia can selectively induce what? This may contribute to immune unresponsiveness to filariasis.
CD4+ lymphocyte apoptosis
What have been associated with tropical pulmonary eosinophilia (TPE), granulomas all the skin, and allergic reactions following destruction by drugs?
Microfilariae
What is a classic example of occult filariasis in which microfilaria are not found in the blood but may be found in the tissues?
TPE
It is characterized by: • paroxysmal cough hypereosinophilia (3,000 - 5,000 cells per mm3) • elevated ESR • bronchopulmonary markings • diffuse military lesions • high IgE titer • good response to diethylcarbamazine
TPE
What are the early manifestations of filariasis?
- fever
- lymphadenitis
Recurrent attacks are characterized by what?
- funiculitis
- arms & legs swelling and redness
- tenderness in affected area (even draft of air is painful)
- vomiting and headache (few days to wks)
The signs and symptoms reflect the immunologic phenomenon caused by sensitization to the products of living or dead worms and are called
ADL adenolymphangitis
Acute episodes of this is one of the symptoms and this acute clinical manifestation is characterised by recurrent attacks of fever associated with inflammation of the lymph nodes and or lymph vessels
adenolymphangitis (ADL)
This is seen in individuals who grew up outside regions and demic for this filarial parasites and who got infected by them after migration to the endemic regions
Expartriate Syndrome
Expartriate Syndrome symptoms
Hives Rashes Bld eosinophilia Lymphadenitis Lymphangitis
This is due to immunological hyperesponsiveness to the mature or matured worms
Expartriate Syndrome
It is due to chronic proliferative overgrowth of fibrous tissue around the dead worms
Chronic stage
Chronic stage changes lead to what?
Lymphatic obstruction
Recurrent attacks of dermatolymphangioadenitis
Lymphedema
Elephantiasis or hydrocoele
The progression in the pathology of elephantiasis is greatly due to what?
Bacterial or fungal superinfection
Development of slow chronic filarial disease
Preceded by chronic oedema at first pitting
Then chronic non pitting edema
And repeated acute inflammatory episodes
How soon can you see lymphedema and elephantiasis?
Lymphedema - as early as 6 months
Elephantiasis - as early as 1 year
What can also be noted in male and female in the chronic stage?
Male: chronic epididymitis, funiculitis, lymphedematous thickening of the scrotal and spermatic cords
Female: lymphedema of the vulva
Which is more severe, bancroftian filariasis or malayan filariasis?
Deformities resulting from bancroftian filariasis
Rupture of lymphatic seen the kidneys may produce what?
Chyluria or milky urine
What is the periodicity of the microfilaria of the brugia malayi?
Subperiodic
What is the best time to collect blood smears for the diagnosis of brugia malayi infection?
At night but they may also be taken during the day using the diethylcarbamazepine provocative test
Demonstration of microfilaria on peripheral blood film or wet smears taken between what time?
8pm to 4am owing to their nocturnal periodicity
What is the case of infection is low intensity, what can be used?
Filtration using a nuclear pore filter or Knott’s method for concentration
What antigen detection techniques are used to detect circulating filarial antigens (CFA)?
- PCR for detection of filarial DNA
- Rapid format immunochromatographic test for w bancrofti antigens
What is the drug of choice for bancroft filariasis?
Diethylcarbamazine citrate (DEC) 6 mg/kg BW, orally for. 12 days in divided doses after meals
What is the drug of choice for brugian filariasis?
Diethylcarbamazine citrate (DEC) 3 mg/kg/day up to a total of 36-72mg/BW
What can be another treatment for filariasis?
Ivermectin in single oral dose of 200-400ug/kg BW
the swelling is no longer reversible
overnight, and the patient may still experience acute attacks.
Stage 2
the swelling increases during the day but is
reversible once the patient lies flat in bed.
Stage 1
presence of shallow skin folds, these are folds
where the base can still be seen when the patient moves the leg or foot and the fold “opens up.” Lines or creases not seen in the normal leg are already considered shallow folds.
Stage 3
there are knobs present in the affected area;
these are lumps or protrusions in the skin that
predispose the area to trauma
Stage 4
has deep skin folds, where the base can no longer be seen when the patient moves the leg, but only when the folds are actively “opened” by hand
Stage 5
mossy lesions are present, brought about by the clustering of small elongated or rounded growths. These usually leak translucent fluid, putting the area at risk for secondary bacterial infection
Stage 6
the patient is unable to adequately or independently perform activities of daily living
due to the extent of the patholgy. The infected
area is foul-smelling and the affected individual frequently experiences acute attacks
Stage 7
The most common chronic manifestation of LF is
lymphedema, which on progression leads to elephantiasis
What is the most common acute
manifestation of LF, defined as localized pain,
lymphadenitis and/or lymphangitis and/or
cellulitis and local warmth, with or without
systemic manifestations of fever, nausea, and
vomiting?
ADLA (Acute Dermatolymphangiodenitis)
What results in the obstruction of the lymphatics of the tunica vaginalis?
Hydrocele or chylocele
Clear or strawcolored hydrocele fluid typically accumulates in the closed sac of the testis, and rarely, the fluid may have a milky appearance caused the presence of lymph—a condition known as
chylocele
What is a common chronic
disease manifestation of Bancroftian filariasis
since W. bancrofti worms have been shown
ultrasonographically to prefer localization in
scrotal lymphatics
hydrocele
What are the genital manifestations of chronic Bancroftian
filariasis?
Chronic epididymitis, funiculitis,
lymphedematous thickening of the scrotal skin,
and thickening of the spermatic cord
What is a classic example of occult filariasis in which the typical clinical manifestations are not present, and microfilaria are not found in the blood but may be found in the tissues?
Tropical pulmonary eosinophilia (TPE)
The syndrome,
which is brought about by immunologic
hyper-responsiveness to filarial infection, is
characterized by paroxysmal nocturnal cough,
hypereosinophilia (3,000-5,000 cells per mm3
of blood, levels unrelated to the severity of
symptoms), elevated erythrocyte sedimentation
rate, evidence of diffuse miliary lesions or
increased bronchovascular markings, extremely
high titers of filarial antibody (IgE), and good
therapeutic response to DEC. In most cases,
lung function is impaired, with a reduction in
vital capacity, total lung capacity, and residual
volume. It is commonly misdiagnosed as asthma
or tuberculosis.
TPE
Chronic symptoms may delay
diagnosis, and if untreated, this may progresses to
chronic pulmonary fibrosis and respiratory
failure.
TPE
Due to the nocturnal
periodicity of most W. bancrofti strains, wet
smears or thick blood smears are taken between
8pm - 4am
What test stimulates microfilariae into coming out to the peripheral
circulation, allowing blood smear collection
even during daytime?
DEC provocative
test (3 mg /kg DEC single dose)
Which among the following may correctly demonstrate the microfilariae?
Biopsy of enlarged lymph nodes immediately proximal to an infected lymphatic tract
Persistence of severe pruritus in the skin
infested with human itch mites will result to
_________.
Excoriation
Treatment of filarial infections
A single dose of Diethylcarbamazine
and Ivermectin of either together
with an oral dose of Albendazole is
given
