Parasitology - Introduction to Tissue Nematodes and Filarial Worms

1. By: Ferle C. Estera/Velez college student/afraid of cockroaches

2. How are intestinal nematodes differ from tissue nematodes?

3. • Suborder: Spirurida
• Suborder: Camallanina Species: Dracunculus medinensis
Superfamily:
Filarioidea
Thelazioidea
Species:Onchocerca volvulus , Loa loa,
Mansonella , Dirofilaria repens,
Wuchereria bancrofti, Brugia malayi,
Brugia timori
Species: Gnathostoma spinigerum

4.  The Camallanina are a suborder of nematodes.
 Species: Dracunculus medenensis (human as final host)
 Parasites of terrestrial and aquatic vertebrates
 Copepods as obligatory secondary hosts

5. Thelazioidea is a superfamily of spirurian nematodes in the
large order Spirurida. Like all nematodes, they have neither a circulatory nor a
respiratory system.
Species: Gnathostoma spinegerum

6.  Family: Acanthocheilonematidae

7. What are the common filarial spp. in man?

8.  Live in tissues or body cavities of a vertebrate host
 Slender, threadlike worm usually 2 to 1 cm
 Common habitat: circulatory system, lymphatic system, connective tissue and
serous cavities
 These are transmitted by blood sucking insects
 Requires two hosts to complete the cycle.

9.  Produces less differentiated microfilariae
 Microfilariae- are highly motile, threadlike pre larva that in some species may retain egg
membrane as SHEATH or it raptures to become naked or UNSHEATHED
 Microfilaria are capable of living a long time in the vertebrate host, but cannot develop further until
ingested by an intermediate host.
 Microfilariae transforms into infective larvae in the insect and are deposited in the next host when
insect takes its blood meal
• Female worms are viviparous
• Males are smaller than females

10. Sheathed Unsheathed
• Burgia malayi,
• Wuchereria bancrofti
• Loa loa
• M. Perstans
• M. Ozzardi
• M. Streptocerca
• O. volvulus

12.  Infective third stage larvae are transmitted to man by infected biting arthropods
during a blood meal
 Inside the arthropod, the microfilariae develop in 1 to 2 weeks into infective
filariform (third stage larvae)
 The adults dwell in various human tissues where they can live for several years
 Larva migration and development takes place in the tissue
 Definitive host: man

13.  Nocturnal- largest no. of microfilariae found in peripheral blood is at night
 Diural- Largest no. of microfilariae found in peripheral blood during day
 Non periodic- largest no. of microfilariae circulating at some what constant levels
during day and night
 Sub periodic- Microfilariae detected throughout the day but are detected in a
larger number during late afternoon

14. Parasites Adult Microfilaria Periodicity Vector
LYMPHATIC
W. bancrofti Lymphatic blood Nocturnal culex, aedes, anopheles
B. malayi Lymphatic blood Nocturnal Aedes, anoph, mansoni
B. timori Lymphatic blood Nocturnal Anopheles
SUBCUTANEOUS
L. loa Connective blood Diurnal chrysops
O. volvulus Connective skin Non periodic Simulium
M. streptocerca Dermis skin Non periodic Culicoides
SEROUS CAVITY
M. perstans Body cavity blood Non periodic Culicoides
M. ozzardi Body cavity blood Non periodic Culicoides
L o c a t i o n i n b o d y

15. Blood concentration technique
Knott’s concentration technique: 2% formaldehyde,
centrifuge, methanol, giemsa smear
Membrane filtration: Nucleopore, Syringe

18.  Clinical manifestations mainly by the adult worms
 Immunologic responses, both humoral and cell-mediated
 Dead or dying worms elicit the most severe inflammation
 Calcification of necrotizing granulomas with dead worms lead to lymphatic
obstruction

19.  Acute filarial disease “acute attacks”
 Episodes of febrile lymphangitis and lymphadentis
 Adenolymphangitis (ADL) dermatoadenolyphangitis (DADL)
 Pain, tenderness and swelling of affected areas (limbs, genitals, breast) w/ or
w/out fever
 Epididymo-orchitis in males may occur

20. Lymphedema- An abnormal
accumulation of lymph in tissues
causing swelling of legs , arms, breasts,
or genitals
Elephantiasis- disabling and
disfiguring lymphedema of the limbs,
breast and genitals, accompanied by
marked thickening of the skin
PRESENCE OF PARASITE IN LYMPHATIC
SYSTEM CAN LEAD TO:

21. Hydrocele- Fluid-filled
ballon-like enlargement of
the sacs around the testes
Kidney damage- leading to
blood and protein loss in
urine
PRESENCE OF PARASITE IN LYMPHATIC
SYSTEM CAN LEAD TO:

22. treatmentDiagnosisLocation in
human
Mode of
transmission
DiseaseNematode
species
Surgical
extraction
clinicalSubcutaneous,
mainly in lower
limbs
Ingestion of
infected
cyclops in
water
Dracunculias
is, Guinea
worm disease
Dracunculus
medinensis
NON-FILARIAL TISSUE NEMATODE INFECTIONS

23. MAJOR FILARIAL INFECTIONS OF HUMANS
Lab.
diagnosis
vectorLocation of
microfilaria
Location of
adult in
humans
Geographic
distribution
Diseasespecies
Blood filmmosquitoesBlood
(nocturnal
periodicity)
Lymphatic
vessels
Tropical
and
subtropical
areas
elephantiasisWuchereria
bancrofti
Blood filmmosquitoesBlood
(nocturnal
periodicity)
Lymphatic
vessels
AsiaelephantiasisBrugia
malayi
Skin snipSimulium
spp. (black
fly)
Skin, eyes,
no
periodicity
Subcutaneous
nodules
Africa,
Central
and South
America,
Yemen
Onchocerciasi
s (river
blindness)
Onchocerca
volvulus
Blood filmChrysops
spp. (deer
fly)
Blood
(diurnal
periodicity)
Moving in
subcutaneous
tissues
Central
Africa
loiasisLoa loa