Intro to Helminths Flashcards
Nematodes reproduction?
separate sexes
Trematodes reproduction?
hermaphroditic (schistosome group has separate sexes)
Cestodes reproduction?
hermaphroditic
PATHOGENESIS OF NEMATODES (ROUNDWORMS)
what 2 worms?
Acaris lumbricoides and wuchereia bancrofti
Ascaris lumbricoides have what type of host?
humans and swine
Occasionally, Ascaris eggs may be found in
ASCARIS LUMBRICOIDES
dog feces
Ascariasis is the ____ ____ ____ helminthic infection globally
Ascaris lumbricoides
most common human
The burden is highest in _____ & ___ regions, especially in areas with inadequate/poor sanitation
Ascaris lumbricoides
tropical and subtropical
Common in areas where human feces are used as
Ascaris lumbricoides
fertilizer
Infection is generally ____ to absent in developed countries, but sporadic cases may occur in rural,____ regions of those countries.
Ascaris lumbricoides
- rare
- impoverished
Some cases in these areas where human transmission is negligible have direct epidemiologic associations to
Ascaris lumbricoides
- pig farms
Adult worms usually cause __ acute symptoms
ASCARIS LUMBRICOIDES CLINICAL FEATURES
no
Heavy infections in children may cause ____ growth because of ____
ASCARIS LUMBRICOIDES CLINICAL FEATURES
- stunted
- malnutrition
clinical feature of what worm?
High worm burdens may cause fever, vomiting, distention, abdominal pain, and intestinal obstruction and potentially perforation in very high intensity infections
ASCARIS LUMBRICOIDES CLINICAL FEATURES
Because the worm has a tough, flexible body, it can occasionally perforate the intestine, creating ____ with _____ _____
ASCARIS LUMBRICOIDES CLINICAL FEATURES
peritonitis with secondary bacterial infection
Migrating adult worms may cause symptomatic occlusion of the biliary tract (resulting in liver and
ASCARIS LUMBRICOIDES CLINICAL FEATURES
damage tissue), appendicitis, or nasopharyngeal expulsion
Ascaris may produce pneumonitis resembling an ____ ____
ASCARIS LUMBRICOIDES CLINICAL FEATURES
asthmatic attack
____ are long, slender roundworms that are parasites of blood, lymph, subcutaneous, and connective tissues
WUCHERERIA BANCROFTI
Filariae
Most produce larval worms called
WUCHERERIA BANCROFTI
microfilariae
Transmitted by ___ or ____
WUCHERERIA BANCROFTI
mosquitoes or biting flies
W. bancrofti is transmitted by many different mosquito genera/species, depending on geographical
WUCHERERIA BANCROFTI
distribution: Aedes spp., Anopheles spp., Culex spp., Mansonia spp., and Coquillettida juxtamansonia.
Occurs in ____ and ____ areas
WUCHERERIA BANCROFTI
tropical and subtropical
what worm?
It is currently endemic throughout Sub-Saharan Africa (excluding the southern portion of the continent), Madagascar, several Western Pacific Island nations, and territories and parts of the Caribbean
WUCHERERIA BANCROFTI
_____ ____ also occurs sporadically in South America, India, and Southeast Asia
WUCHERERIA BANCROFTI
Bancroftian filariasis
In some patients, there is no sign of disease, even though blood specimens may show the presence of
WUCHERERIA BANCROFTI CLINICAL FEATURES
microfilariae
In other patients, early acute symptoms include fever, lymphangitis and
WUCHERERIA BANCROFTI CLINICAL FEATURES
lymphadenitis with chills, and recurrent febrile attacks
The acute presentation results from the inflammatory response to the presence of molting adolescent worms and dead or dying adults within the(think in the body)
WUCHERERIA BANCROFTI CLINICAL FEATURES
lymphatic vessels
Physical obstruction of lymph in the vessels caused by the presence of adult worms causes enlargement of the lymph nodes, including the enlargement of the extremities, the scrotum, and the testes, with occasional abscess formation
WUCHERERIA BANCROFTI CLINICAL FEATURES
progresses to filarial elephantiasis
Affected limbs become grossly swollen; the skin may become thick and pitted, and secondary infection are frequent due to
WUCHERERIA BANCROFTI CLINICAL FEATURES
lymphatic dysfunction
Lymphangitis, lymphadenopathy, and eosinophilia may accompany infection in the
WUCHERERIA BANCROFTI CLINICAL FEATURES
in the early stages.
Tropical pulmonary eosinophilia (TPE) is a syndrome caused by immune hyperresponsiveness to
WUCHERERIA BANCROFTI CLINICAL FEATURES
microfilariae trapped in the lungs
what disease and worm?
Patient presents with wheezing, chest pain, splenomegaly, and bloody sputum
Tropical pulmonary eosinophilia (TPE)
WUCHERERIA BANCROFTI CLINICAL FEATURES
what disease and worm?
Paroxysmal cough and wheezing are usually nocturnal, weight loss, low-grade fever, and adenopathy and pronounced blood eosinophilia (≥3000 eosinophils/μl)
Tropical pulmonary eosinophilia (TPE)
WUCHERERIA BANCROFTI CLINICAL FEATURES
Pathogenesis of Cestodes
review slide
One of largest tapeworms infecting humans (20 to 30 feet long)
DIPHYLLOBOTHRIUM LATUM
Occurs worldwide, most prevalently in cool lake regions where ___ or ___ ___ is popular
DIPHYLLOBOTHRIUM LATUM
raw or pickled fish
Intermediate and paratenic hosts include a wide diversity of freshwater and marine fishes, commonly
DIPHYLLOBOTHRIUM LATUM
perch and pike
The global trade and consumption of wild-caught fish leads to human cases occurring regularly
DIPHYLLOBOTHRIUM LATUM
outside of naturally endemic regions
what worm?
In addition to humans, other carnivorous, fish-eating mammals, and a few birds can also serve as hosts
DIPHYLLOBOTHRIUM LATUM
what worm?
Non-human hosts include a variety of carnivorous mammals: canids, felids, bears, and mustelids
(weasels, badgers, otters, ferrets, martens, minks and wolverines)
DIPHYLLOBOTHRIUM LATUM
what worm?
Dumping raw sewage into freshwater lakes contributes to propagation of this tapeworm
DIPHYLLOBOTHRIUM LATUM
Most infections are
DIPHYLLOBOTHRIUM LATUM
asymptomatic
Symptoms include epigastric pain, abdominal cramping, nausea, vomiting, and weight loss
DIPHYLLOBOTHRIUM LATUM CLINICAL FEATURES
As many as 40% of D. latum carriers may have low serum levels of
vitamin B12
DIPHYLLOBOTHRIUM LATUM CLINICAL FEATURES
Megaloblastic anemia
(vitamin B12 deficiency)
DIPHYLLOBOTHRIUM LATUM CLINICAL FEATURES
D. latum absorbs approximately ____ of dietary vitamin B12
80% of dietary
DIPHYLLOBOTHRIUM LATUM CLINICAL FEATURES
____ can be a long-lasting infection (up to 25 years)
Diphyllobothriasis
DIPHYLLOBOTHRIUM LATUM CLINICAL FEATURES
Aberrant migration of proglottids can cause ____ or ____
cholecystitis or cholangitis
DIPHYLLOBOTHRIUM LATUM CLINICAL FEATURES
Massive infections may cause
intestinal obstruction
DIPHYLLOBOTHRIUM LATUM CLINICAL FEATURES
what worm?
Neurologic manifestations include numbness, paresthesia, and loss of vibration sense
DIPHYLLOBOTHRIUM LATUM CLINICAL FEATURES
Schistosomiasis (____, ____): major parasitic infection of tropical areas; ≈230 million infections worldwide
bilharziasis, snail fever
SCHISTOSOMA SPP.
Ways Schistosomes differ from other flukes:
Schistosoma Spp.
- male and female sexes (not hermaphroditic)
- oral and ventral suckers
- incomplete digestive system
what worm?
Intermediate hosts are snails of the genera Biomphalaria (S. mansoni), Oncomelania (S. japonicum), Bulinus (S. haematobium)
Schistosoma Spp.
Bio-man,no melanin in japan, bul mat
where is the reservoir?
S. mansoni: most widely distributed; endemic in Africa, Saudi Arabia, Madagascar; has also become established in some South American countries (Brazil, Venezuela, Suriname) and the Caribbean
Reservoir hosts include primates, marsupials, and rodents
Schistosoma Spp.
S. japonicum (Oriental blood fluke):
found only in China, the Philippines, and on the island of Sulawesi in Indonesia
Despite its name, it has long been eliminated from Japan
Schistosoma Spp.
Reservoir hosts include cattle, dogs, cats, rodents, pigs, horses, and goats
S. japonicum (Oriental blood fluke): found only in China, the Philippines, and on the island of Sulawesi in Indonesia
Schistosoma Spp.
where is the reservoir?
S. haematobium: occurs predominantly throughout the Nile Valley and many other parts of Africa
Reservoir hosts include monkeys, baboons, and chimpanzees
Schistosoma Spp.
Many infections are
SCHISTOSOMA CLINICAL FEATURES
asymptomatic
Schistosoma Spp.
Disease results primarily from
Schistosoma Spp.
host immune response to eggs; clinical significance directly related to number and location of eggs
A local cutaneous hypersensitivity reaction following skin penetration by
cercariae may occur and appears as small, itchy maculopapular lesions.
Schistosoma Spp.
____ ___ is a systemic hypersensitivity reaction that may occur weeks after the initial infection, especially by S.mansoni and S. japonicum.
Acute schistosomiasis (Katayama fever)
Schistosoma Spp.
Manifestations include systemic symptoms/signs including fever, cough, abdominal pain, diarrhea,
hepatosplenomegaly, and eosinophilia.
Schistosoma Spp.
Occasionally, Schistosoma infections may lead to
Schistosoma Spp.
central nervous system lesions.
Cerebral granulomatous disease may be caused by ectopic S. japonicum eggs in the brain, and
Schistosoma Spp.
granulomatous lesions around ectopic eggs in the spinal cord may occur in S. mansoni and S. haematobium infections.
Continuing infection may cause granulomatous reactions and
fibrosis in the affected organs (e.g., liver and spleen) with associated signs/symptoms
Schistosoma Spp.
Pathology associated with S. mansoni and S. japonicum schistosomiasis includes various hepatic complications from inflammation and granulomatous
reactions, and occasional embolic egg granulomas in brain or spinal cord.
Schistosoma Spp.
Pathology of S. haematobium schistosomiasis includes hematuria, scarring, calcification, squamous cell carcinoma, and occasional embolic egg
Schistosoma Spp.
granulomas in brain or spinal cord.
Clinical manifestations of chronic infection: hepatosplenomegaly and cirrhosis, esophageal varices, bladder neck obstruction, squamous cell bladder
Schistosoma Spp.
carcinoma, transverse myelitis, and other forms of central nervous system involvement