[DISCUSSION] MODULE 3 UNIT 2 AND UNIT 3 Flashcards

1
Q

 The phylum Nematoda is divided into classes based on the presence or absence of “(?)’, which are caudal chemoreceptors.

A

phasmids

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2
Q

 The two (2) classes were earlier called Aphasmidia and Phasmidia, but now have been renamed as (?), respectively.

A

Adenophorea and Secernentea

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3
Q

 The origin of the name (Gr. trichos = hair + oura = the tail), is not quite correct because it is the (?) of the worm that is hair-like and not the tail.

A

anterior end

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4
Q

 Whipworm

A

A. Trichuris trichiura

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5
Q

Infection is caused by ingestion of embryonated eggs.

A

A. Trichuris trichiura

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6
Q

 Eggs – hatch in the small intestine.

A

A. Trichuris trichiura

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7
Q

 larvae (L1) – released and penetrate the intestinal villi and undergo 4 molts in 3-10 days.

A

A. Trichuris trichiura

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8
Q

 young adult – passively migrate to the cecum (also in the ascending colon) and mature in about 2-3 months

A

A. Trichuris trichiura

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9
Q

 usually asymptomatic, except in heavy infection

A

Trichuriasis

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10
Q

 Heavily infected individuals - those with a high worm burden (greater than 200 worms, >5,000 EPG)- are most likely to
develop clinical disease.

A

Trichuriasis

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11
Q

 hypochromic, microcytic type

A

Iron-deficiency anemia

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12
Q

 results from chronic blood loss at the attachment site coupled with the long life span of the worms

A

Iron-deficiency anemia

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13
Q

 Small amounts of blood (0.005 ml per worm) are lost each day at the ulceration in the intestinal mucosa

A

Iron-deficiency anemia

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14
Q

 worm may be found even up to the rectum in heavy infection

A

Rectal prolapse

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15
Q

 mucosa of the rectum protrudes through the anal opening associated with the loss of muscle tone of the anus

A

Rectal prolapse

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16
Q

 Children with severe trichuriasis have:
o growth retardation
o impaired mental development
o cognitive function

A

Sever Trichuriasis

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17
Q

 Pudoc worm

A

B. Capillaria philippinensis

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18
Q

 In 1967, an epidemic of Capillariasis took place in
Pudoc West, Tagudin, Ilocos Sur

A

B. Capillaria philippinensis

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19
Q

Infection is caused by ingestion of larvae in raw or
undercooked infected fish

A

B. Capillaria philippinensis

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20
Q

 larvae - develop into adults in the small intestine
(jejenum) where they burrow into the mucosa

A

B. Capillaria philippinensis

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21
Q

 Female worms - may produce two types of eggs:
o Unembryonated shelled eggs –
passed in the feces
o Embryonated eggs – hatches
within human host

A

B. Capillaria philippinensis

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22
Q

 larvae - will re-invade and cause autoinfection.

A

B. Capillaria philippinensis

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23
Q

 unembryonated eggs - ingested by fish when
passed into water.

A

B. Capillaria philippinensis

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24
Q

 malabsorption syndrome with severe diarrhea

A

Intestinal capillariasis

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25
 borborygmi (gurgling stomach)
Intestinal capillariasis
26
 abdominal pain (can become serious if not treated because of autoinfection)
Intestinal capillariasis
27
 Capillary liver worm
C. Capillaria hepatica
28
 The nematode (roundworm) Capillaria hepatica (=Calodium hepaticum) causes hepatic capillariasis in humans.
C. Capillaria hepatica
29
 Nomenclature varies in use globally and by discipline; Capillaria hepatica is most frequently used in medical literature.
C. Capillaria hepatica
30
 zoonotic parasite with a low host specificity o primarily exists in rodent and carnivore hosts o Both true and spurious infections occur in humans
C. Capillaria hepatica
31
Infection is caused by ingestion of embryonated eggs in fecally- contaminated food, water, or soil
C. Capillaria hepatica
32
 Adult worms - are located deep within the liver parenchyma of the host, and lay hundreds of eggs in the surrounding parenchymal tissue.
C. Capillaria hepatica
33
 eggs - trapped in the parenchyma; can not be passed in the feces of the host, and remain in the liver until the animal dies, or more likely, is eaten by a predator or scavenger
C. Capillaria hepatica
34
o Eggs ingested by scavengers are unembryonated (not infectious) and are passed in through the digestive tract into and out in feces, providing an efficient mechanism to release eggs back into the environment
C. Capillaria hepatica
35
o Eggs embryonate in the environment, where they require air and damp soil to become infective.
C. Capillaria hepatica
36
 Under natural conditions, embryonation is slow and may take between 6 weeks and 5 months.
C. Capillaria hepatica
37
 The cycle continues when embryonated eggs are eaten by a suitable mammalian host.
C. Capillaria hepatica
38
 Infective eggs hatch in the intestine, releasing first stage larvae.
C. Capillaria hepatica
39
 The larvae penetrate the intestinal wall and migrate via the portal vein to the liver parenchyma within 3-4 days.
C. Capillaria hepatica
40
 Larvae take about 3-4 weeks to mature into adults and mate.
C. Capillaria hepatica
41
 rare in humans
Hepatic capillariasis
42
 typically manifests as an acute or subacute hepatitis with: o peripheral leukocytosis and eosinophili o hepatomegaly o persistent fever (which may be as high as 40°C)
Hepatic capillariasis
43
 Trichina worm
D. Trichinella spiralis
44
 The name Trichinella is derived from the minute size of the adult (Gr. trichos =hair, ella suffix for diminutive) and spiralis refers to the spirally coiled appearance of larvae in muscles.
D. Trichinella spiralis
45
Infection is caused by ingestion of raw/rare or undercooked meat containing encysted larvae
D. Trichinella spiralis
46
 Adult worms and encysted larvae develop within: o 1 vertebrate host o definitive host and potential intermediate host : infected animal o A second host is required to perpetuate the life cycle of Trichinella.
D. Trichinella spiralis
47
 domestic cycle o pigs o anthropophilic rodents o other domestic animals  horses
D. Trichinella spiralis
48
 sylvatic cycle o bear o moose o wild boar
D. Trichinella spiralis
49
 After exposure to gastric acid and pepsin, the larvae are released from the cysts (excystation) invade the small bowel mucosa, molt four times and rapidly develop into adults, either male or female, by the 2nd day of infection.
D. Trichinella spiralis
50
 Within 5 days, they become sexually mature
D. Trichinella spiralis
51
 The male dies after fertilizing the female.
D. Trichinella spiralis
52
 After 1 week of infection, the fertilized females release larvae.
D. Trichinella spiralis
53
 Larvae continue to be discharged during the remaining part of the lifespan of the female worm, which ranges from 4 weeks to 4 months.
D. Trichinella spiralis
54
 These larvae enter the intestinal lymphatics or mesenteric venules and are transported in circulation to different parts of the body. o They get deposited in the muscles, central nervous system and other sites.
D. Trichinella spiralis
55
 The larvae die in most other situations, except in the skeletal muscles, where they grow.
D. Trichinella spiralis
56
 Within 20 days after entering the muscle cells, the larvae encyst within nurse cells.
D. Trichinella spiralis
57
 Encysted larvae lie parallel to the muscles of host and can survive for months to years and eventually calcify and die.
D. Trichinella spiralis
58
 In man, the life cycle ends here. o Man is a dead-end host of the parasite, as the cysts in human muscles are unlikely to be eaten by another host.
D. Trichinella spiralis
59
 Trichinella spiralis has an unusual life cycle in that the same individual animal serves as both definitive and intermediate host, adults and larvae located in different organs.
D. Trichinella spiralis
60
 autoheteroxenous parasite
D. Trichinella spiralis
61
Cysts develop preferentially in muscles relatively poor in glycogen and in hypoxic environment. o Therefore, the biceps, deltoid, gastrocnemius, pectoralis, masseter, extraocular muscles, intercostal muscles and diaphragm, which are constantly active, are the ones mostly affected.
D. Trichinella spiralis
62
- gastrointestinal symptoms  diarrhea  abdominal pain  vomiting
Intestinal phase
63
 high fever  periorbital and facial edema  conjunctivitis  blurred vision  myalgias  splinter hemorrhages  rashes  peripheral eosinophilia lasting 1 month in heavy infection Occasional life-threatening manifestations:  myocarditis  central nervous system involvement  pneumonitis
Migration phase
64
 myalgia and weakness o followed by subsidence of symptoms
Larval encystment
65
 abdominal tenderness and pain  weight loss  weakness  mucoid or bloody stool
A. Trichuris trichiura
66
 Cosmopolitan  Tropical and subtropical countries with warm and moist soil.
A. Trichuris trichiura
67
Global  604 to 795 million o Children
A. Trichuris trichiura
68
Phlippines  4.5 to 55.1% o preschool children  8.1 to 57.9% o school-age children
A. Trichuris trichiura
69
 Natural host: Humans
A. Trichuris trichiura
70
 morphologically similar worms are found to infect: o pigs o dogs o some monkeys
A. Trichuris trichiura
71
 At risk: ↑ children
A. Trichuris trichiura
72
 Area: poor sanitation practices are common o open defecation o night soil as fertilizer
A. Trichuris trichiura
73
 Mechanical vectors: o House flies o Cockroaches
A. Trichuris trichiura
74
Symptoms  severe protein-losing enteropathy and hypoalbuminemia  malabsorption of fats and sugars  decreased excretion of xylose  low serum potassium, sodium and calcium  high levels of IgE  Serious cases may be fatal in 2 weeks to 2 months.
B. Capillaria philippinensis
75
 Endemic o Ilocos Norte, Ilocos Sur, Cagayan, La Union, Pangasinan, Zambales, Agusan del Norte, Leyte o More:  Zamboanga del Norte o Few:  Zamboanga del Sur  Agusan del Sur  Misamis Occidental.
B. Capillaria philippinensis
76
 Twice as many males as females become infected.
B. Capillaria philippinensis
77
 Males are mostly fishermen who partake of the days catch.
B. Capillaria philippinensis
78
 Definitive host/Reservoir: Fish-eating birds  Intermediate host o fresh or brackish water fish
B. Capillaria philippinensis
79
 Migratory birds o parasite is widely distributed throughout Asia and elsewhere
B. Capillaria philippinensis
80
 deposition of eggs in the liver parenchyma causes: o granuloma formation and liver necrosis, which in heavy infections can lead to potentially fatal liver dysfunction
C. Capillaria hepatica
81
 Cosmopolitan in wildlife o Human cases have originated from all inhabited continents except for Australia, although it exists in wildlife
C. Capillaria hepatica
82
 The prevalence in humans may be underestimated due to the nonspecific clinical presentation and difficulty of diagnosis
C. Capillaria hepatica
83
 Typical host: rodents such as rats o has a low host specificity
C. Capillaria hepatica
84
 Infections have also been identified in: o wild and domestic carnivores o humans
C. Capillaria hepatica
85
 contaminated food is ingested  human feces are not the source of contamination  feces of carnivores or flesh-eating rodents are involved
C. Capillaria hepatica
86
 Other symptoms vary depending on the location and number of larvae present
D. Trichinella spiralis
87
 Cosmopolitan o most common in Europe and America o rarely reported in the tropics
D. Trichinella spiralis
88
 It occurs particularly in members of the meat-eating population but the prevalence is low
D. Trichinella spiralis
89
 pig  deer  bear  walrus  rat
D. Trichinella spiralis
90
 ingestion of contaminated pork scraps by pigs
D. Trichinella spiralis
91
 ingestion of contaminated infected rats by pigs – ubiquitous in pig farms
D. Trichinella spiralis
92
 ingestion of contaminated meat by other animals
D. Trichinella spiralis
93
 ingestion of contaminated pork meat by humans o Cooking meat to 60ºC or freezing (20 days in a normal freezer or at - 20°C for 3 days) will kill larvae. o Smoking, salting or drying the meat does not destroy the infective larvae.
D. Trichinella spiralis
94
The Trichinella cycle that is maintained in nature occurs among cannibalistic and carrion-feeding carnivores
D. Trichinella spiralis
95
 Giant intestinal worm
A. Ascaris lumbricoides
96
Infection is caused by ingestion of embryonated eggs.
A. Ascaris lumbricoides
97
 Larvae invade the intestinal mucosa, and are carried via the portal, then systemic circulation on to the heart, then into the lungs
A. Ascaris lumbricoides
98
 The larvae break out of the capillaries into the alveoli.
A. Ascaris lumbricoides
99
 The larvae (L4s) mature further in the lungs (10-14 days), after a molt, penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed.
A. Ascaris lumbricoides
100
 Upon reaching the small intestine, they develop into adult worms.
A. Ascaris lumbricoides
101
 Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female.
A. Ascaris lumbricoides
102
 Adult worms can live 1 to 2 years.
A. Ascaris lumbricoides
103
 Unfertilized eggs may be ingested but are not infective.
A. Ascaris lumbricoides
104
 Larvae develop to infectivity within fertile eggs after 18 days to several weeks, depending on the environmental conditions (optimum: moist, warm, shaded soil).
A. Ascaris lumbricoides
105
Clinical manifestations of ascariasis are caused by the (?) of the: o Larvae o adult worms in the small intestine o wandering adult worms
pulmonary migratory phase
106
The (?) causes allergic reaction.
larval migration
107
The initial exposure to larvae during the (?) is usually asymptomatic, except when the larval load is heavy.
lung migration phase
108
 asthmatic respiration  cough with bronchial rales  chest pain
A. Ascaris lumbricoides
109
These symptoms may be due to the petechial hemorrhages and massive destruction of the lung parenchyma as the larvae break through the capillaries on their way to the alveolar sacs, in massive infection, the hemorrhage may give rise to Ascaris pneumonitis.
A. Ascaris lumbricoides
110
The pulmonary clinical features subside in 1 or 2 weeks after infection. Due to (?) in the blood stream, the larvae may lodge in vital organs such as the brain and spinal cord, the eyeball and the kidney.
larval migration
111
Clinical manifestations due to adult worm vary from asymptomatic infection to severe and even fatal consequences.
A. Ascaris lumbricoides
112
The (?), when present, are caused by spoliative action, toxic action, mechanical effects and wandering effects
pathological effects
113
 The adult worms in the lumen of the small intestine feed on the liquid nutrient in the intestinal fluids.
A. Ascaris lumbricoides
114
 The nutritional effects are usually seen when there is heavy worm burden.
A. Ascaris lumbricoides
115
 The worms interfere with proper digestion and absorption of food.
A. Ascaris lumbricoides
116
 Ascariasis may contribute to protein-energy malnutrition and vitamin A deficiency.
A. Ascaris lumbricoides
117
The (?) are due to hypersensitivity to the worm antigens and may be manifested as fever, urticaria and edema.
toxic effects
118
Ascariasis may cause complications due to (?). Masses of worms (Ascaris bolus) may cause intestinal obstruction.
mechanical effect
119
(?) is a complication of ascariasis due to a few factors, e.g. fever, use of anesthesia during surgery, and worms seeking mates.
Ectopic migration
120
 The worm may migrate up or down along the intestine. o It may block the biliary or pancreatic ducts causing acute biliary obstruction or pancreatitis.
A. Ascaris lumbricoides
121
 It may enter the liver parenchyma causing liver abscesses.
A. Ascaris lumbricoides
122
 The worm may go up the esophagus and come out through the mouth, nose, or ears. o It may obstruct the appendix causing appendicitis. It may lead to peritonitis when it perforates the intestine.
A. Ascaris lumbricoides
123
 This tendency makes preoperative deworming necessary before gastrointestinal surgery in endemic areas. The wandering worm may also reach kidneys.
A. Ascaris lumbricoides
124
 most common human helminthic infection
A. Ascaris lumbricoides
125
 ↑ tropical and subtropical regions o embryonated eggs  can survive in moist shaded soil for a few months to about 2 years in tropical and subtropical areas, but for much longer in temperate regions
A. Ascaris lumbricoides
126
 inadequate sanitation
A. Ascaris lumbricoides
127
 rare to absent in developed countries
A. Ascaris lumbricoides
128
 sporadic cases may occur in rural, impoverished regions of those countries
A. Ascaris lumbricoides
129
 Some cases in these areas where human transmission is negligible have direct epidemiologic associations to pig farms.
A. Ascaris lumbricoides
130
Global  billion  ↑ children  co-exists with Trichuris trichiura
A. Ascaris lumbricoides
131
Phlippines  80-90%  Risk group: public elementary school children
A. Ascaris lumbricoides
132
 Ascaris lumbricoides – humans
A. Ascaris lumbricoides
133
 Ascaris suum – humans and pigs
A. Ascaris lumbricoides
134
 Fecal-oral route  ↑ children  Night-soil  House-flies and cockroaches
A. Ascaris lumbricoides
135
 Resistance of Ascaris eggs to chemicals – lipid layer of their eggshell o 2%  Formalin  potassium dichromate o 50%  Hydrochloric  Nitric  Acetic  Sulfuric acid
A. Ascaris lumbricoides
136
 Pinworm, seatworm  Former name: Oxyuris vermicularis
B. Enterobius vermicularis
137
Infection occurs from ingestion of infective eggs
B. Enterobius vermicularis
138
 These eggs hatch in the small intestine, and the adults establish themselves in the colon, usually in the cecum
B. Enterobius vermicularis
139
 The time interval from ingestion of infective eggs to oviposition by the adult females is about one month.
B. Enterobius vermicularis
140
 At full maturity adult females measure 8-13 mm, and adult males 2-5 mm; the adult life span is about two months.
B. Enterobius vermicularis
141
 Gravid females migrate nocturnally outside the anus and oviposit while crawling on the skin of the perianal area.
B. Enterobius vermicularis
142
 The larvae contained inside the eggs develop (the eggs become infective) in 4 to 6 hours under optimal conditions
B. Enterobius vermicularis
143
? – infected individuals may reinfect themselves  infective eggs are ingested via hand-to-mouth contamination due to scratching of perianal area with fingers → deposition of eggs under the nails. o ↑ children
Autoinfection
144
 eggs laid on the perianal skin immediately hatch into the infective stage larva and migrate through the anus → develop into worms in the cecum
Retroinfection
145
 one-third are asymptomatic
Enterobiasis or oxyuriasis
146
 worm produces intense itching of the perianal area (pruritus ani) and also the perineal area, when it crawls out of the anus to lay eggs o scratching and irritation of the skin around the anus o may give rise to secondary bacterial infection o Children infected – insomnia due to the pruritus
Enterobiasis or oxyuriasis
147
 poor appetite  weight loss  irritability  nocturnal enuresis (involuntary urination)  grinding of teeth  abdominal pain
B. Enterobius vermicularis
148
not associated with eosinophilia or with elevate lgE
B. Enterobius vermicularis
149
In female patients  worms may cause (?) when they crawl into the vulva and vagina causing irritation
ectopic migration
150
 It may migrate up to the uterus and fallopian tubes
B. Enterobius vermicularis
151
 This may cause symptoms of: o Cervicitis o chronic salpingitis o peritonitis o recurrent urinary tract infections
B. Enterobius vermicularis
152
 The worm is sometimes found in surgically removed appendix and has been claimed to be responsible for appendicitis.
B. Enterobius vermicularis
153
 Cosmopolitan o both temperate and tropical areas
B. Enterobius vermicularis
154
Global  ↑ temperate regions and urban areas  Enterobiasis – most common helminth infection in the United States
B. Enterobius vermicularis
155
Phlippines  29% - schoolchildren from exclusive private schools  56% - public schools  16% - females  9% - males
B. Enterobius vermicularis
156
 Natural host: Humans
B. Enterobius vermicularis
157
 Rare: airborne – inhaled and swallowed
B. Enterobius vermicularis
158
 anus-to-mouth o contaminated fingers or other objects in the mouth o inhalation of dust containing Enterobius eggs
B. Enterobius vermicularis
159
 cool moist conditions – eggs remains viable for about 2 weeks
B. Enterobius vermicularis
160
 warm, dry conditions – eggs begin to lose their infectivity within 2 days
B. Enterobius vermicularis
161
Factors:  Overcrowding  wearing soiled clothing  lack of adequate bathing and poor personal hygiene o especially among young school-aged children  Finger sucking and nail biting o may be sources of recurrent infection in children  sexual activity o oral and anal sex  extremely contagious and can easily spread among members of a family or in institutions o familial or a group disease
B. Enterobius vermicularis
162
Two (2) species of hookworms are human parasites:  Necator americanus - New world hookworm  Ancylostoma duodenale - Old world hookworm
C. Hookworms
163
Infection occurs from penetration of filariform larvae (L3) larvae
C. Hookworms
164
 Infective stage are filariform larvae (L3) that penetrate the skin and are carried through the blood vessels to the heart and then to the lungs. o penetrate into the pulmonary alveoli o ascend the bronchial tree to the pharynx o are swallowed o reach the jejunum of the small intestine  reside and mature into adults
C. Hookworms
165
 Adult worms live in the lumen of the small intestine, typically the distal jejunum, where they attach to the intestinal wall by means of well-developed mouth parts (cutting plates in N. americanus and teeth in A. duodenale)
C. Hookworms
166
 Eggs are passed in the stool, and under favorable conditions
C. Hookworms
167
 Larvae hatch in 1 to 2 days and become free-living in contaminated soil. o These released rhabditiform (L1) larvae grow in the feces and/or the soil, and after 5 to 10 days (and two molts) they become filariform (third-stage) larvae that are infective
C. Hookworms
168
Hookworm disease (?) manifests three main phases of pathogenesis
necatoriasis or ancylostomiasis
169
 filariform larvae penetrate skin
the invasion or cutaneous period
170
 do little damage to superficial layers, since they seem to slip unbroken skin through hair follicles, or pores
the invasion or cutaneous period
171
 usual sites of infection: o the dorsum of the feet or between the toe o the hands, especially interdigital spaces
the invasion or cutaneous period
172
 Once in the dermis, however, their attack on blood vessels initiates a tissue reaction.
the invasion or cutaneous period
173
 If, as it usually happens, pyogenic bacteria are introduced into skin with the invading larva, a severe local itching known as ground itch, dew itch, or coolie itch will result
the invasion or cutaneous period
174
 Erythematous papular rash develops when a large number of larvae penetrate the skin. o This is a self-limiting condition, lasting for 2 to 4 weeks
the invasion or cutaneous period
175
 larvae break out of the lung capillary bed into alveoli and progress up bronchi to the throat.
the migration or pulmonary phase
176
 Each site hemorrhages slightly, with serious consequences in massive infections; however, very large numbers of larvae migrating through the lungs simultaneously are rare
the migration or pulmonary phase
177
 The phase is usually asymptomatic, although there may be some dry coughing and sore throat.
the migration or pulmonary phase
178
 A pneumonitis and Loeffler’s syndrome may occur in heavy larvae infection
the migration or pulmonary phase
179
 Asymptomatic
the intestinal phase
180
 Attachment of the worms to the mucosa with their strong buccal capsule and teeth or cutting plates may stimulate: o Abdominal pain o Nausea o Anorexia
the intestinal phase
181
 Adult worms suck blood aided by the anticoagulant that they secrete.
the intestinal phase
182
 The worms change feeding sites and the old biting sites will continue to bleed.
the intestinal phase
183
 Blood loss per worm is about 0.03 ml per day for N. americanus and about 0.15-0.25 ml per day for A. duodenale.
the intestinal phase
184
 Thus, in heavy infection, a substantial amount of blood can be lost, and a severe iron-deficiency (microcytic, hypochromic) anemia may develop in a short time.
the intestinal phase
185
 Nevertheless, a moderate hookworm infection will gradually produce an iron-deficiency anemia as body reserves of iron are used up
the intestinal phase
186
 Patients have reported vague gastrointestinal disturbances and eosinophilia (sometimes referred to as Wakana syndrome) following peroral infection
the intestinal phase
187
 Cosmopolitan
C. Hookworms
188
 N. americanus – tropical Africa and the Americas
C. Hookworms
189
 A. duodenale – Europe and Southwestern Asia
C. Hookworms
190
 But now, both species have become widely distributed throughout the tropics and subtropics, and rigid demarcations are no longer present
C. Hookworms
191
Global  25%
C. Hookworms
192
Phlippines  5-45%
C. Hookworms
193
 N. americanus – 97%  A. duodenale – 1%  mixed infections – 2%
C. Hookworms
194
 Principal host: Humans
C. Hookworms
195
 percutaneous transmission of filariform larvae from the soil
necatoriasis and ancylostomiasis
196
 oral route o eating raw vegetables contaminated with infective filariform larvae o A. duodenale may remain dormant in the intestines or in the muscles, resulting in a prolonged incubation period and creating problems in treatment.  Transmammary o larvae are able to pass into the mammary glands of the mother, so that the newborn baby can receive a large dose of infective larvae through its mother’s milk o cases of heavy and sometimes fatal hookworm infections in children a month or so of age
ancylostomiasis
197
 Ancylostoma caninum (dog hookworm)  Ancylostoma braziliense (cat hookworm)
D. Zoonotic hookworms
198
 The larvae produce itching papules, which develop into serpigenous tracks in the epidermis called (?) or creeping eruption. o These tracts can elongate by several centimeters a day; larvae can migrate for upto one year until they die, but the lesions usually heal spontaneously within weeks to months. o Secondary pyogenic infection may occur at these sites.
cutaneous larva migrans (CLM)
199
 Definitive host: dogs and cats
D. Zoonotic hookworms
200
 Threadworm o UK and Australia – pinworm or seatworm (Enterobius vermicularis)
E. Strongyloides stercoralis
201
 Free-living cycle - Heterogonic cycle  Parasitic cycle - Homogonic
E. Strongyloides stercoralis
202
 Rhabditiform larvae in the gut become infective filariform larvae that can penetrate either the intestinal mucosa (internal autoinfection) or the skin of the perianal and perineal area (external autoinfection).
Autoinfection
203
 They ultimately enter the lymphatics or venules and are carried to the right heart and the lungs to complete the life cycle as earlier, or disseminate throughout the body
Autoinfection
204
 benign and asymptomatic
Strongyloidiasis
205
 only indications of infection o Eosinophilia and larvae in stool
Strongyloidiasis
206
 In immunocompromised individuals, it may cause clinical manifestations which may be severe and even fatal
Strongyloidiasis
207
 filariform larvae may enter blood circulation and lodge in various organs, e.g. heart, lungs, brain, kidneys, pancreas, liver and lymph nodes
Disseminated strongyloidiasis
208
- dermatitis, with erythema and itching at the site of penetration of the filariform larva, particularly when large numbers of larvae enter the skin
Cutaneous manifestations
209
- larva currens (meaning racing larvae) has been applied to the rapidly progressing linear or serpiginous urticarial tracks caused by migrating filariform larvae
Cutaneous manifestations
210
- often follow autoinfection and start perianally
Cutaneous manifestations
211
- This rash usually advances very rapidly (up to 10 cm/hr)
Cutaneous manifestations
212
- When the larva escape from the pulmonary capillaries into the alveoli, small hemorrhages may occur in the alveoli and bronchioles. Pneumonia and Loeffler's syndrome may be present in some patients.
Pulmonary manifestations
213
- This may present as malabsorption syndrome. Diarrhea is often present.
Intestinal manifestations
214
- In heavy infection, there may be extensive sloughing of the intestinal mucosa.
Intestinal manifestations
215
 internal autoinfection in immunocompromised
Hyperinfection
216
 large number of worms in the intestine and lungs
individuals
217
 Other manifestations include: o protein losing enteropathy o paralytic ileus
E. Strongyloides stercoralis
218
 Clinical manifestations depend on the sites affected: o Brain abscess o meningitis and peritonitis
E. Strongyloides stercoralis
219
 Cosmopolitan o tropics and subtropics o Europe and the USA o follows a distribution pattern similar to hookworm
E. Strongyloides stercoralis
220
Global  Unknown  Estimate: 30–100 million
E. Strongyloides stercoralis
221
Phlippines  relatively rare
E. Strongyloides stercoralis
222
Host  Humans
E. Strongyloides stercoralis
223
 Rarer human-infecting species of Strongyloides zoonotics: o S. fuelleborni (fülleborni) subsp. fuelleborni o S. fuelleborni subsp. kellyi
E. Strongyloides stercoralis
224
 direct contact with soil contaminated by Strongyloides larvae
E. Strongyloides stercoralis
225
 area: poor sanitation o feces are disposed in the warm moist soil o provide an optimal atmosphere for the organism to exist
E. Strongyloides stercoralis
226
 allows for maintenance of the parasite within the host for years following the initial exposure
Autoinfection
227
 Toxocara canis - dog ascarid  Toxocara cati - cat ascarid
F. Toxocara spp.
228
Ingesting infective eggs or undercooked meat/viscera of infected paratenic hosts
F. Toxocara spp.
229
 Humans are accidental hosts
F. Toxocara spp.
230
 eggs hatch
F. Toxocara spp.
231
 larvae penetrate the intestinal wall and are carried by the circulation to a variety of tissues (liver, heart, lungs, brain, muscle, eyes)
F. Toxocara spp.
232
Toxocara spp. can follow a [?] (one host) or [?] (multiple host) life cycle.
direct indirect
233
 Unembryonated eggs are shed in the feces of the definitive host.
F. Toxocara spp.
234
 Eggs embryonate over a period of 1 to 4 weeks in the environment and become infective, containing thirdstage (L3) larvae.
F. Toxocara spp.
235
 Following ingestion by a definitive host, the infective eggs hatch and larvae penetrate the gut wall
F. Toxocara spp.
236
In younger dogs (T. canis) and in cats (T. cati):  the larvae migrate through the lungs, bronchial tree, and esophagus, where they are coughed up swallowed into the gastrointestinal tract  adult worms develop and oviposit in the small intestine
direct (one host)
237
In older dogs, patent (egg-producing) infections can also occur  larvae more commonly become arrested in tissues  Arrested larvae are reactivated in female dogs during late gestation and may infect pups by the transplacental (major) and transmammary (minor) routes in whose small intestine adult worms become established
direct (one host)
238
In cats, T. cati:  larvae can be transmitted via the transmammary route to kittens if the dam is infected during gestation  somatic larval arrest and reactivation does not appear to be important as in T. canis
direct (one host)
239
 ingestion of paratenic hosts
indirect (multiple host)
240
 Eggs ingested by suitable paratenic hosts hatch and larvae penetrate the gut wall and migrate into various tissues where they encyst
indirect (multiple host)
241
 The life cycle is completed when definitive hosts consume larvae within paratenic host tissue, and the larvae develop into adult worms in the small intestine
indirect (multiple host)
242
 preschool children
visceral larva migrans (VLM)
243
 larvae invade multiple tissues o commonly liver o lung o skeletal muscle o occasionally heart
visceral larva migrans (VLM)
244
 cause various nonspecific symptoms o fever o myalgia o weight los o cough o rashes o hepatosplenomegaly  usually accompanied by hypereosinophilia
visceral larva migrans (VLM)
245
 Migration to the central nervous system
neurotoxocariasis or neural larva migrans
246
 Uncommon
neurotoxocariasis or neural larva migrans
247
 eosinophilic meningoencephalitis
neurotoxocariasis or neural larva migrans
248
 Death o severe cardiac o pulmonary o neurologic involvement
neurotoxocariasis or neural larva migrans
249
 larvae produce various ophthalmologic lesions
(OLM)
250
 may cause diffuse unilateral subacute neuroretinitis (DUSN) o unilateral (affecting one eye) involvement
(OLM)
251
associated visual impairment usually presents with  uveitis, retinitis, or endophthalmitis  permanent visual damage or blindness
F. Toxocara spp.
252
associated larval granulomas  misdiagnosed as retinoblastoma
F. Toxocara spp.
253
 Cosmopolitan o among domestic dogs and cats
F. Toxocara spp.
254
 both animals and people o ↑ developing countries
F. Toxocara spp.
255
 people of lower socioeconomic strata o ↑ developed countries
F. Toxocara spp.
256
 Public places: 10-30%
F. Toxocara spp.
257
 western countries: 25% to 30 to 60% (dogs)
F. Toxocara spp.
258
 Accidental hosts: Humans
F. Toxocara spp.
259
 all wild and domestic canids  puppies o patent infections
Toxocara canis
260
 wild and domestic felids of all ages  kittens o patent infections
Toxocara cati
261
Paratenic hosts: mammals and birds; livestock Paratenic or transport hosts: Cockroaches and earthworms
F. Toxocara spp.
262
 soil-transmitted zoonosis
Human toxocariasis
263
 ↑ children living in homes and in neighborhoods where dogs and puppies are not dewormed o tendency to play in soil o geophagia or soil eating
Human toxocariasis
264
 Poor personal hygiene
Human toxocariasis
265
 consumption of inadequately washed vegetables chronic low-dose infections
Human toxocariasis
266
 consumption of undercooked beef, lamb, chicken, and duck meat (particularly liver)
Human toxocariasis