1. Ectoparasites 2. Endoparasites

1. Intermediate 2. Definitive 3. Reservoir

Parasite Flashcards by Cherie Rosemarie Balorio

An organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it.

Parasite

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2 terms of Parasite

Obligate
Facultative

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Parasite that can live only in association with a host.

Obligate

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Parasites can live both in or on a host as well
as in a free form

Facultative

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Parasites that cause harm to the host

Pathogenic

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Parasites while those that benefit from the host without causing it any harm

Commensals

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2 types of parasites

Ectoparasites
Endoparasites

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organisms that live on or in other living organisms
called the hosts.

Parasites

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3 types of hosts

Intermediate
Definitive
Reservoir

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The hosts that harbor the larval and asexual stage.
It is the host which harbors the immature stage of the parasite.
Example: Snails in Trematodes

Intermediate Host

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The hosts which harbors the adult stage
of the parasite.
The parasite attains sexual maturity in it.
Example: Dog for Ancylostoma caninum; Cattle for Fasciola gigantica

Definitive Host

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Ensure continuity of the parasite’s life cycle and act as additional sources of human infection.
It is a vertebate host in which parasite occurs naturally.
The host harbors the parasite but does not produce harm to the host.

Reservoir Host

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It means parasitic worms.
They are multicellular, eukaryotic organisms in the Kingdom Animalia.

Helminths

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2 Major Divisions of Helminths

Nematoda/Nematodes (Roundworms)
Platyhelminthes (Flatworms)

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They are elongated and tapered at both ends, rounds in cross section, and unsegmented.

Nematoda/Nematodes (Roundworms)

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-They have only a set of longitudinal muscles, which allows them to move in a whiplike, penetrating fashion; a complete digestive system that is well adapted for ingestion of the host’s gut contents, cells, blood, or cellular breakdown products

Nematoda/Nematodes (Roundworms)

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Most human infections are acquired by ingestion of
the (1) ____ or ______ , but nematode infections can
also be acquired from (2)_____ and _____.

Egg or Larval Stage
Insect Vectors and Skin Penetration

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Are dorsoventrally flattened in cross section and are hermaphroditic

Platyhelminthes (Flatworms)

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2 types of Platyhelminthes

Cestodes
Trematodes

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Are flat and have a ribbon-like chain of segments (proglottids) containing male and female reproductive structures.
Adult ______ have no mouth or gut and absorb their nutrients directly from their host through their integument.

Cestodes (Tapeworms)

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-Are typically flattened and leaf shaped with two muscular suckers.
-Hermaphroditic, with the exception of the schistosomes (blood flukes), which have male and female worms that exist coupled together within small blood vessels of their hosts.

Trematodes (Flukes)

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3 Major Stages in Helminth Life Cycle

Egg
Larva
Adult

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Trematodes are hermaphroditic, with the exception of the
________ (blood flukes), which have male and female worms
that exist coupled together within small blood vessels of their
hosts.

Schistosomes

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5 Intestinal Tramatodes

Ascaris lumbricoides
Enterobius vermicularis
Necator americanus
Strongyloides stercoralis
Trichuris trichiura

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CN: Large Intestinal Roundworm IH: None DH: Human Infection acquired: Ingestion of Eggs Infection diagnosed: Observation of stool specimen (40-70 mm by 35-50 mm)

Ascaris lumbricoides

- Depends on the number of worms - Worms subsist on liquid content of small intestines - Do not suck blood or graze on mucosa - Small to Medium infections are usually asymptomatic

Ascaris lumbricoides

- May cause "sensitization phenomenon" - Allergic reaction to worm waste - Rashes, eye pain, asthma, insomia, restlessness

Ascaris lumbricoides

- Overcrowding can lead to wandering upstream to pancreatic or bile ducts; causes liver damage. - It reaches stomach, causes vomiting of worm: or downstream to appendix or out anus

Ascaris lumbricoides

- Females like to crawl through small spaces (also larger than male) - Male worm has curly tail - May crawl through nose, ear or any other opening - Aspiration of worm can cause death

Ascaris lumbricoides

- Affects all ages, more prevalent in the 5-9 years, incidence is higher in poor rural populations

Ascaris lumbricoides

▪Some people has no symptoms ▪Others: abdominal pain, weight loss, anorexia, distended abdomen, intermittent loose stool, occasional vomiting ▪ Heavy infections-block the intestine ▪ Pulmonary stage – cough, wheezing, dyspnea, sub-sternal discomfort

Ascaris lumbricoides

Diagnosis ▪ Microscopic examination of stool ▪ Identification of adult worms in stool or emerging from the nose, mouth, or rectum ▪ Larvae in sputum (Larvae pulmonary phase) ▪ Chest X-ray: show signs of infiltrates (Larvae pulmonary phase) ▪ Radiographic studies: worm in the GIT

Ascaris Lumbricoides

3 drugs that may harm the fetus if taken when diagnosed with Ascariasis

Albendazole, Mebendazole, Ivermectin

Before treatment with this drug, patients should be assessed for co-infection with Loa Loa if they have lived in areas of central Africa where Loa loa is endemic because this drug can cause severe reactions in patients with loiasis and high microfilarial levels.

Ivermectin

Drug effective for mild infections and not for heavy infections of Ascaris lumbricoides

Nitazoxanide

Drug once widely used but replaced by less toxic alternatives to cure Ascaris lumbricoides

Piperazine

CN: Pinworm IH: None DH: Human Infection Acquired: Ingestion of Eggs Infection Diagnosed: Observation of eggs in “Scotch Tape Method”, "Cellophane Method" or "Pinworm Paddle"

Enterobius vermicularis

Symptoms * Perianal, perineal and vaginal irritation caused by the female migration * Itching results in insomnia and restlessness * Gastrointestinal symptoms (pain, nausea, vomiting, etc.) may develop

Enterobius vermicularis

Drug given for patient with Enterobius vermicularis; two weeks apart gives a very high cure rate.

Pyrental Pamoate

Drus used to lessent the numbers of pinworm

Albendazole

Alternative drug for pinworms

Mebendazole

CN: New World Hookworm IH: None DH: Human Infection Acquired:Penetration of skin by infective larva Infection Diagnosed:Observation of eggs in stool specimens

Necator americanus

Adult worms attach to intestinal villi with their buccal teeth and feed on blood and tissue (can cause severe anemia and iron deficiency)

Necator americanus

* Symptoms: Abdominal discomfort and diarrhea * Initial skin infection: Ground itch (characterized by erythema(abnormal redness of the skin) and intense pruritus (intense itching)

Necator americanus

Feet and ankles are common site of infection due to exposure from walking barefoot

Necator americanus

Treatment and control for Necator americanus: * ___________ for adults and 100 mg for children, for 3 days is effective. * Sanitary disposal of fecal material * Avoidance of contact with infected fecal material

Mebendazole

CN: Threadworm/ Cochin-china diarrhea IH: None DH: Human Infection Acquired: Penetration of skin by infective larva Infection Diagnosed: Observation of eggs in duodenal aspirates or stool specimens

Strongyloides stercoralis

* Less than 10 worms are asymptomatic * Heavier infections (e.g., massive infantile trichuriasis) - chronic profuse mucus and bloody diarrhea (can cause anemia) with abdominal pains and edematous prolapsed rectum

Trichuris trichiura

3 drugs taken when infected with T. trichiura

Albendazole, Mebendazole, Ivermectin

Oral ______ is available for human use in the United States

Albendazole

(5) Blood and Tissue Nematodes

1. Dracunculus medinensis 2. Trichinella spiralis 3. Brugia Malayi 4. Wucheria bancrofti 5. Loa Loa

CN: Guinea Worm; Fiery Serpent IH: Cyclops (fresh water crustacean) DH: Human INFECTION ACQUIRED: Ingestion of infected Cyclops INFECTION DIAGNOSED: Observation of adult worm beneath the skin or emerging from a blister (ankle or foot)

Dracunculus medinensis

- The female worm induces a painful blister. After a rupture of the blister, the worm emerges as a whitish filament - Loves lymphatic nerves

Dracunculus medinensis

* If the worm does not reach the skin, it dies and causes little reaction. * Superficial tissue - inflammatory reaction in the form of a sterile blister with serous exudation.

Dracunculus medinensis

* The worm lies in a subcutaneous tunnel with its posterior end beneath the blister, which contains clear yellow fluid. * The course of the tunnel is marked with induration and edema. * Contamination of the blister produces abscesses, cellulitis, extensive ulceration and necrosis.

Dracunculus medinensis

Treatment * Extraction of the adult guinea worm * No drug is effective in killing the worm. * Protection of drinking water from being contaminated with Cyclops and larvae

Dracunculus medinensis

CN: None IH/DH: Pig, Bear, Walrus, Human (dead-end host) and etc. INFECTION ACQUIRED: Ingestion of pork or bear meat with larva INFECTION DIAGNOSED: Usually not diagnosed or an incidental finding at autopsy

Trichinella spiralis

The larvae in the tissue are coiled in a lemon-shaped capsule.

Trichinella spiralis

* Pathogenesis is due the presence of large numbers of larvae in vital muscles and host reaction to larval metabolites * Muscle fibers become enlarged edematous and deformed * Paralyzed muscles are infiltrated with neutrophils, eosinophils and lymphocytes.

Trichinella spiralis

Diagnosis for this parasite is eating raw or undercooked meat, laboratory findings (eosinophilia, increased serum creatine phosphokinase and lactate dehydrogenase and antibodies to ______).

Trichinella spiralis

Drug used for patients infected with T. spiralis

-Albendazole -Mebendazole( worm elimination)

CN: Whipworm IH: None DH: Human INFECTION IS ACQUIRED: Ingestion of eggs INFECTION DIAGNOSED: Observation of eggs in stool specimens

Trichuris trichiura

* parasitic/free-living worm * female is larger

Strongyloides stercoralis

* Light infections are asymptomatic. * Skin penetration causes itching and red blotches. * During migration, the organisms cause bronchial verminous pneumonia and, in the duodenum, they cause a burning mid-epigastric pain and tenderness accompanied by nausea and vomiting.

Strongyloides stercoralis

* Diarrhea and constipation may alternate. * Heavy, chronic infections - anemia, weight loss and chronic bloody dysentery.

Strongyloides stercoralis

First line therapy for S. stercoralis

Ivermectin

Alternative drug for S. stercoralis

Albendazole

Therapeutic drug option for S. stercoralis but was discontinued

Thiabendazole

CN: None IH: Various species of mosquitoes. INFECTION IS ACQUIRED: Injection of infective larvae by mosquito INFECTION DIAGNOSED: Observation of microfilariae in stained blood specimens

Brugia malayi/Wuchereria bancrofti

The most prominent clinical feature is the development of severe lymphedema of the limbs

Elephantiasis

occasionally genitalia (a type of swelling in the scrotum that occurs when fluid collects in the thin sheath surrounding a testicle) due to dysfunction of lymphatic vessels.

Hydrocele

• Affected limbs become grossly swollen; the skin may become thick and pitted, and secondary infection are frequent due to lymphatic dysfunction. • Scrotal hydrocele is also seen in some infected males. • Lymphangitis, lymphadenopathy, and eosinophilia may accompany infection in the early stages.

Filariasis/Elephantiasis

An elderly male with hydrocoele, elephantiasis of the leg, hanging groin, leopard skin and onchocerciasis nodules.

Filariasis/Elephanthiasis

CN: Eye Worm IH: Chrysops ( Mango Fly) INFECTION IS ACQUIRED: Injection of infective larvae by Chrysops INFECTION IS DIAGNOSED: Observation of adult worm beneath the skin or in the conjunctiva of the eye

Loa Loa

The MDA (Mass Drug Administration) regimen recommended depends on the co- endemicity of lymphatic filariasis with other filarial diseases. WHO recommends the following MDA regimens:

Albendazole, Ivermectin, Diethylcarbamazine citrate

- cylindrical, has a cuticle with three main outer layers made of collagen and other compounds which protects the nematodes so they can invade the digestive tract of animals -adults are small, thin worms

Loa Loa

Ecosystem roles: An obligate endoparasite, feeding on fluids in the tissues of humans.

— Infect human host by travelling from the entry site through the SQ causing inflammation in the skin (Calabar swelling). — These are localized, inflammatory, pruritic subcutaneous edema seen in joints of extremities (wrist and ankle) due to allergens and metabolic products released by the worm.

Loa Loa

— It can also travel and infect the eye. — In deeper tissues, it can cause encephalitis. — Common symptoms are itching, joint pain, fatigue and death.

Loa Loa

3 Drugs used to treat Loa Loa

Diethylcarbamazine, Albendazole, Apheresis (followed by DEC)

CN: Blinding Worm/ River Blindness IH: Simulium (Black Fly) DH: Human INFECTION IS ACQUIRED: Injection of infective larvae by Simulium INFECTION IS DIAGNOSED: Observation of microfilariae in “skin snips”

Onchocerca volvulus

— Palpation of a subcutaneous nodule. — Nodules that were surgically removed contain coiled adult worms.

Onchocerca volvulus

Treatment for O.volvulus

Ivermectin (for microfilariae) Doxycycline (for macrofilariae)

CN: Beef Tapeworm IH: Cow DH: Human INFECTION IS ACQUIRED: Ingestion of infected beef INFECTION IS DIAGNOSED: Observation of egg or proglottids in the stool specimen

Taenia saginata

CN: Pork Tapeworm IH: PiDH: Human INFECTION IS ACQUIRED: Ingestion of infected pork INFECTION IS DIAGNOSED: Observation of egg or proglottids in stool specimen; cysticercosis (CT scans, MRI techniques, x-ray or immunodiagnostic procedures

Taenia solium

Drug used for patient diagnosed with T. saginata/solium

Praziquantel or Niclosamide

CN: Giant Intestinal Fluke IH: Fresh Water Snails DH: Human, Dog, Pig, Rabbit INFECTION IS ACQUIRED: Ingestion of raw or uncooked plants on which metacercariae are encysted INFECTION IS DIAGNOSED: Observation of eggs in stool specimens

Fasciolopsis buski

— This is a parasite of central and southeast Asia. — Elongate oval fluke; lives in the small intestine

Fasciolopsis buski

Man is infected by ingesting water chestnuts contaminated with metacercaria which find access to the small intestine, attach themselves to the mucosa and mature in 25 to 30 days. The fluke eggs are passed in the feces and hatch in fresh water producing miracidia which must penetrate a suitable snail within hours. The miracidia in the snail develop into cercaria and enter fresh water where they attach themselves to water plants (water chestnut) and encyst to become metacercaria

Fasciolopsis buski

— Epigastric pain, nausea and diarrhea(morning). — Edema and ascites - heavier infections — The fluke attaches itself to the intestinal mucosa where inflammation, ulceration and abscesses occur.

Fasciolopsis buski

Treatment and Control for F. buski

- Praziquantel - Water chestnuts from contaminated waters should be avoided. - Sewage should be treated before disposal.

CN: Chinese or Oriental Liver Fluke IH: Fresh Water Snails (1st IH); Fresh Water, Fish (2nd IH) DH: Human, Dog, Cat INFECTION IS ACQUIRED: Ingestion of infected fresh water fish INFECTION IS DIAGNOSED: Observation of eggs in stool specimens

Clonorchis sinensis

CN: Liver Fluke IH: Fresh Water Snails DF: Human, Cow, Sheep INFECTION IS ACQUIRED: Ingestion of raw or undercooked aquatic vegetation (water cress) with metacercariae INFECTION IS DIAGNOSED: Observation of eggs in stool specimens

Fasciola hepatica

• Humans are infected by the consumption of improperly cooked watercress that harbors encysted larval metacercariae. • The larval fluke penetrates the duodenal wall and migrates to the peritoneal cavity, penetrates the liver capsule and migrates into the bile duct where it matures. • The adult fluke passes its eggs in stool that hatch in water to produce miracidia. • The miracidium must find an appropriate snail to continue the life cycle. • In the snail, the miracidium divides and gives rise to cercariae which exit the snail and encyst as metacercariae attached to watercress leaves.

Fasciola hepatica

— tenderness of the liver and hepatomegaly which results in upper quadrant pain, chills and fever accompanied with eosinophilia. The toxic secretions cause hepatitis. — bile duct - irritation resulting in hyperplasia of the epithelium and bile obstruction. Adult worms may invade the liver and cause necrotic foci (liver rot).

Fasciola hepatica

Drug used to treat patients infected with F.hepatica

Triclabendazole

CN: Lung Fluke IH: Fresh Water Snails(1ST IH); Crabs or Crayfish (2ND IH) DH: Human, Dog, Cat INFECTION IS ACQUIRED: Ingestion of infected crabs or crayfish INFECTION IS DIAGNOSED: Observation of eggs in rust colored sputum (often for TB) or stool specimens

Paragonimus westermani

— most commonly encountered in parts of Asia, Africa and South America — plump reddish brown oval worm; ovum

Paragonimus westermani

• When crabmeat infested with encysted metacercaria is consumed. • The metacercaria reach the small intestine, exit their shell and bore their way, as young flukes, through the intestinal wall, through the thoracic diaphragm and penetrate the lung. • There, they become enclosed in cysts and reach maturity. • The eggs are found in the sputum or, if swallowed, in the feces, 2 to 3 months after infection. • The eggs, when introduced in fresh water produce a miracidia which penetrates the suitable snail. • In the snail they develop into cercaria which break out in water and penetrate gills, muscle or viscera of fresh water crabs and become encysted in flesh as metacercaria

Paragonimus westermani

• dry cough, followed by production of blood stained rusty brown sputum • Pulmonary pain and pleurisy may develop. • brain where they lay eggs - granulomatous abscess resulting in symptoms similar to epilepsy.

Paragonimus westermani

Treatment and Control for P. westermani

▪ Praziquantel ▪ Adequate cooking of crustaceans. ▪ Improved sanitary conditions.

CN: Blood Fluke IH: Fresh Water Snails DH: Human INFECTION IS ACQUIRED: Penetration of skin by cercariae present in fresh water INFECTION IS DIAGNOSED: Observation of eggs in urine

Schistosoma haematobium

CN: Blood Fluke IH: Fresh Water Snails DH: Human INFECTION IS ACQUIRED: Penetration of skin by cercariae present in fresh water INFECTION IS DIAGNOSED: Observation of eggs in stool

Schistosoma japonicum and Schistosoma mansoni

— Adult worms are 10 to 20 mm long; the male has an unusual lamelliform shape with marginal folds forming a canal in which the slender female worm resides. — Unlike other trematodes, they have separate sexes

Schistosoma spp.

▪ skin - dermatitis (swimmers' itch),splenomegaly, lymphadenopathy and diarrhea ▪ bladder -granulomatous lesions, hematuria , urethral occlusion. ▪ intestine - polyp formation which, in severe cases, may result in life threatening dysentery ▪ liver - periportal fibrosis and portal hypertension resulting in hepatomegaly, splenomegaly and ascites. A gross enlargement of the esophageal and gastric veins may result in their rupture.

Schistosoma spp

— CNS and cause headache, disorientation, amnesia and coma. — Eggs carried to the heart produce arteriolitis and fibrosis resulting in enlargement and failure of the right ventricle

Schistosoma japonicum

• Man is infected by cercaria in fresh water by skin penetration. • The cercaria travel through the venous circulation to the heart, lungs and portal circulation. • In about 3 weeks, they mature and reach the mesenteric for the duration of the host's life. • Eggs germinate as they pass through the vessel wall into the intestine or bladder and are excreted in feces • In fresh water, the larval miracidium hatches out of the egg and swims about until it finds an appropriate snail. • After two generations of multiplication in the snail, the fork-tailed cercariae emerge into the water and infect another human.

S. japonicum and S. mansoni

• Man is infected by cercaria in fresh water by skin penetration. • The cercaria travel through the venous circulation to the heart, lungs and portal circulation. • In about 3 weeks, they mature and reach the bladder vessels where they live and ovulate for the duration of the host's life. • Eggs germinate as they pass through the vessel wall into urine • In fresh water, the larval miracidium hatches out of the egg and swims about until it finds an appropriate snail. • After two generations of multiplication in the snail, the fork-tailed cercariae emerge into the water and infect another human.

S. hematobium

Treatment and Control for Schistosoma spp.

▪ Praziquantel ▪ Contaminated water should be avoided. ▪ sanitary disposal of sewage and destruction of snails ▪ No vaccine is available.

— eukaryotic, usually single-celled — animal-like microorganisms (nutrient needs and cellular structure — most of them are free-living organisms found in soil and water, some live in animal hosts

Protozoa

One cell splits into two

Fission

A form of asexual reproduction characteristic of certain protozoa, including sporozoa, in which daughter cells are produced by multiple fission of the nucleus of the parasite followed by segmentation of the cytoplasm to form separate masses around each smaller nucleus.

Schizogony

Buds form around a nucleus and pinch off of the parent cell

Budding

– locomotory organelle; cell extensions that flow in direction of travel

Pseudopods

– locomotory organelles; numerous short protrusions that propel organisms through its environment

Cilia

– locomotory organelles; extensions of cells that are fewer, longer and more whiplike than cilia

Flagella

The stages of parasitic protozoa that actively feed and multiply

Trophozoites

— Are stages with a protective membrane or thickened wall. — Protozoan ____ that must survive outside the host usually have more resistant walls than _____ that form in tissues.

Cysts

DISEASE: Amebiasis; Amebic Dysentery; Extraintestinal amebic abscesses HOW ACQUIRED: Ingestion of cysts in contaminated water and food HOW DIAGNOSED: Observation of cysts and/or trophozoites in fecal specimens; serology; nuclei have sharp central karyosome and fine chromatin spikes

Entamoeba histolytica

- Inverted, flask-shaped lesions in the large intestine with extension to the peritoneum and liver, lungs, brain, and heart - Blood and pus in the stools - Liver abscesses (most severe complications)

Entamoeba histolytica

•Acute: Frequent dysentery with necrotic mucosa and abdominal pain. •Chronic: Recurrent episodes of dysentery with blood and mucus in the feces. —There are intervening gastrointestinal disturbances and constipation. — Cysts are found in the stool. — The organism may invade the liver, lung and brain where it produces abscesses that result in liver dysfunction, pneumonitis, and encephalitis.

Entamoeba histolytica

- Treatment for E. histolytica - used to treat asymptomatic infections

Iodoquinol

- Treatment for E. histolytica - Used for symptomatic and chronic amebiasis, including extra-intestinal disease.

Mebendazole

- Giardiasis - Ventral sucking disk attaches to lining of duodenal wall causing a fatty, foul-smelling diarrhea - diarrhea - malabsorption HOW ACQUIRED: ingestion of cysts in contaminated water and food HOW DIAGNOSED: Observation of cysts and/ or trophozoites in fecal specimens

Giardia lamblia (Flagellate)

• Early symptoms - flatulence, abdominal distension, nausea and foul- smelling bulky, explosive, often watery, diarrhea. • The stool contains excessive lipids but very rarely any blood or necrotic tissue. • Chronic stage is associated with vitamin B12 malabsorption, disaccharidase deficiency and lactose intolerance.

Giardia lamblia (Flagellate)

• Covering of the intestinal epithelium by the trophozoite and flattening of the mucosal surface results in malabsorption of nutrients.

Giardia lamblia (Flagellate)

- There is some role for IgA and IgM and there is increased incidence of infection in immunodeficient patients (e.g.AIDS).

Giardia lamblia (Flagellate)

Trophozoite: half pear-shaped organism with 8 flagella and 2 axostyles arranged in a bilateral symmetry. There are two anteriorly located large suction discs. The cytoplasm contains two nuclei and two parabasal bodies

Giardia lamblia (Flagellate)

2 forms of protozoa

1. Trophozoites 2. Cysts

Cyst: Ellipsoidal cells with a smooth well-defined wall. The cytoplasm contains four nuclei and many of the structures seen in the trophozoite.

Giardia lamblia (Flagellate)

•Diagnosis: distinct from other dysenteries due to lack of mucus and blood in the stool and lack of high fever. •Treatment: Metronidazole

Giardia lamblia (Flagellate)

DISEASE: Trichomoniasis; causes about one-third of cases of vaginitis - Abnormal alkalinity of the vagina favors disease - Asymptomatic - Frothy, malodorous, yellow-green vaginal discharge - Inflammation of the vagina (strawberry vagina), vulva, cervix HOW ACQUIRED: trophozoites; sexual contact; fomites HOW DIAGNOSED: Observation of trophozoites of vaginal or urethral discharge or prostatic secretions in methylene blue wet mount

Trichomonas vaginalis (Flagellate)

- 5% in normal females and as high as 70% among prostitutes and prison inmates. - Trophozoite and is half pear shaped with a single nucleus, four anterior flagella and a lateral flagellum attached by an undulating membrane. - Two axostyles are arranged asymmetrically. The organism does not encyst.

Trichomonas vaginalis (Flagellate)

— rarely symptomatic in men, although it may cause mild urethritis or occasionally prostatitis. In women, it is often asymptomatic, but heavy infections in a high pH environment — may cause mild to severe vaginitis with copious foul-smelling yellowish, sometimes frothy discharge.

Trichomonas vaginalis

In Woman: • Vaginal fluid that smells bad and is greenish or yellowish • Genital itching, burning, redness, or soreness • Pain when they pee or have sex • The need to pee more often • Bleeding after sex

Trichomonas vaginalis

In Men: • Itching or irritation inside their penis • A thin white discharge from the penis • Pain when they pee or have sex • The need to pee more often

Trichomonas vaginalis

Treatment for T. Vaginalis

▪Metronidazole (although teratogenic) is effective in both males and females. ▪ Vinegar douche may be useful. ▪ Personal hygiene and the use of condoms are helpful.

DISEASE: African Trypanosomiasis (African Sleeping Sickness) HOW ACQUIRED: Injection of the parasite when a Tsetse fly takes a blood meal HOW DIAGNOSED: Observation of trypano-mastigotes in blood or CSF specimens or lymph node aspirates

Trypanosoma brucie

• Symptoms can be divided into three stages: the bite reaction (chancre), parasitemia (blood and lymphoid tissues), and CNS stage. • Bite reaction: A non-pustular, painful, itchy chancre forms 1-3 weeks after the bite and lasts 1-2 weeks. It leaves no scar.

Trypanosoma brucie

Parasitemia: • Fever starts 2-3 weeks after the bite • Malaise • Insomnia • Headache • Lymphadenopathy • Edema

Trypanosoma brucie

CNS Stage • Changes in character and personality • Lack of interest and disinclination to work • Avoidance of acquaintances • Morose and melancholic attitude alternating with exaltation • Mental retardation and lethargy • Low and tremulous speech • Tremors of tongue and limbs • Slow and shuffling gait • Altered reflexes, etc. • Males become impotent. • The later stages are characterized by drowsiness and uncontrollable urge to sleep. • The terminal stage is marked by wasting and emaciation. Death results from coma, intercurrent infection or cardiac failure.

Trypanosoma brucie

Diagnosis — Parasite in the bloodstream, lymph secretions and enlarged lymph node aspirate provides a definitive diagnosis in early (acute) stages. — The parasite in blood can be concentrated by centrifugation or by the use of anionic support media. — Cerebrospinal fluid must always be examined for organisms.

Trypanosoma brucie

Treatment and Control for T. brucie

• Blood stage - Pentamidine isethionate or Suramin but increase the risk of CNS disease. • Cases with CNS involvement should be treated with Melarsoprol, an organic arsenic compound. • The most effective means of prevention is to avoid contact with tsetse flies. • Vector eradication is impractical due to the vast area involved. • Immunization has not been effective due to antigenic variation.

DISEASE: American Trypanosomiasis (Chagas’ Disease) HOW ACQUIRED: Parasites in the feces of a Reduviid (“kissing”) bug get rubbed into bug bite wound HOW DIAGNOSED: Observation of trypano-mastigotes in blood or CSF specimens or lymph node aspirates; tissue biopsy

Trypanosoma cruzi

Symptoms • The primary lesion, chagoma, appearing at the site of infection, within a few hours of a bite, consists of a slightly raised, flat non-purulent erythematous plaque surrounded by a variable area of hard edema. • It is usually found on the face, eyelids, cheek, lips or the conjunctiva, but may occur on the abdomen or limbs. • When the primary chagoma is on the face, there is an enlargement of the pre and post- auricular and the submaxillary glands on the side of the bite. • Infection in the eyelid, resulting in a unilateral conjunctivitis and orbital edema (Ramana's sign) is the commonest finding.

Trypanosoma cruzi

Acute Stage: • The acute stage appears 7-14 days after infection. • It is characterized by restlessness, sleeplessness, malaise, increasing exhaustion, chills, fever and bone and muscle pains. • Other manifestations of the acute phase are cervical, axillary and iliac adenitis, hepatomegaly, erythematous rash and acute myocarditis.

Trypanosoma cruzi

Chronic Stage: • The acute stage is usually not recognized and often resolves with little or no immediate damage and the infected host remains an asymptomatic carrier. • An unknown proportion (guessed at 10-20%) of victims develop a chronic disease. They alternate between asymptomatic remission periods and relapses characterized by symptoms seen in the acute phase. • Cardiac arrhythmia is common. Treatment: — Nifurtimox or benznidazole

Trypanosoma cruzi

DISEASE: Leishmaniasis HOW ACQUIRED: Injection of the parasite when a Phelobotomus “Sand fly” takes a blood meal HOW DIAGNOSED: Observation of parasite in aspirates or biopsy specimens

Leishmania spp.

Symptoms • L. donovani organisms in visceral leishmaniasis are rapidly eliminated (rare local lesion) • Minute papules have been described in children • One to four months after infection, there is occurrence of fever, with a daily rise to 102-104 degrees F, accompanied by chills and sweating. • Spleen and liver enlarged • With progression of the diseases, skin develops hyperpigmented granulomatous areas (kala-azar means black disease).

Leishmania spp • Visceral leishmaniasis (kala-azar, dumdum fever):

Many children suffering from this develop a noticeable thickening, stiffening and darkening of the eyelashes and eyebrows.

Visceral leishmaniasis

• The organism (L. tropica) multiplies locally, producing of a papule, 1-2 weeks (or as long as 1-2 months) after the bite. • Painless ulcer • The center of the ulcer encrusts while satellite papules develop at the periphery. • The ulcer heals in 2-10 months, even if untreated but leaves a disfiguring scar

Cutaneous leishmaniasis (Oriental sore, Delhi ulcer, Baghdad boil)

• The initial symptoms of mucocutaneous leishmaniasis are the same as those of cutaneous leishmaniasis, except that in this disease the organism can metastasize and the lesions spread to mucoid (oral, pharyngeal and nasal) tissues and lead to their destruction and hence severe deformity. • The organisms responsible are L. braziliensis, L. mexicana and L. peruviana.

Mucocutaneous leishmaniasis (Espundia, Uta, Chiclero)

Diagnosis • Diagnosis is based on a history of exposure to sandfies, symptoms and isolation of the organisms from the lesion aspirate or biopsy, by direct examination or culture. • A skin test (delayed hypersensitivity: Montenegro test) and detection of anti-leishmanial antibodies by immuno-fluorescence are indicative of exposure.

Leishmania spp

Treatment and Control: • Sodium stibogluconate (Pentostam) is the drug of choice. • Pentamidine isethionate is used as an alternative. • Control measures involve vector control and avoidance. • Immunization has not been effective.

Leishmania spp.

DISEASE: Malaria HOW ACQUIRED: Injection of sporozoites when a female Anopheles mosquito takes a blood meal HOW DIAGNOSED: Observation of trophozoites, schizonts, and/or gametocytes in blood specimens; antigen testing

Plasmodium spp.

1. Infection (Anopheles mosquito): — A1. Injects sporozoite into blood to liver 2. Liver phase (7-14 days) —2A. Schizont to merozoite (all) — 2B. hypnozoite (P. ovale and P. vivax) 3. RBC phase — 3a. Merozoites infects RBC — 3b. Trophozoites lyse RBC thus infects RBC — 3c. Gametocytes taken up by mosquito

Plasmodium spp.

Symptoms • Incubation period: 10-30 days • Parasite load becomes significant: headache, lassitude, vague pains in the bones and joints, chilly sensations and fever. • Disease progresses: Chills and fever become more prominent. • The chill and fever follow a cyclic pattern (paroxysm) with the symptomatic period lasting 8-12 hours. In between the symptomatic periods, there is a period of relative normalcy, the duration of which depends upon the species of the infecting parasite.

Plasmodium spp.

• Without treatment, all species of human malaria may ultimately result in spontaneous cure except with P. falciparum which becomes more severe progressively and results in death. • This organism causes sequestration of capillary vasculature in the brain, gastrointestinal and renal tissues. • Chronic malaria results in splenomegaly, hepatomegaly and nephritic syndromes.

Plasmodium spp.

Produces fever every 72 hrs or 3 days which is the so called “Quartan malaria”

Plasmodium Malariae

Produces fever every 48 hours hence called the “Tertian Malaria”

Plasmodium Vivax and Plasmodium Ovale

Produces fever every 36-48 hours which is also known as “Malignant Tertian Malaria”

Plasmodium falciparum

• Treatment is effective with various quinine derivatives (quinine sulphate, chloroquine, meflaquine and primaquine, etc.). • Drug resistance, particularly in P. falciparum and to some extent in P. vivax is a major problem. • Control measures are eradication of infected anopheline mosquitos. • Vaccines are being developed and tried but none is available yet for routine use.

Treatment and control for Plasmodium spp.

DISEASE: Toxoplasmosis HOW ACQUIRED: Ingestion of oocysts from cat feces or cysts in contaminated meat HOW DIAGNOSED: Immunodiagnostic procedures; tonsil and lymph gland biopsy

Toxoplasma gondii

Symptoms • Congenital infections: Result in miscarriage, serious brain, eye damage to the fetus, visual handicaps • Although 58-70% of infected women will give birth to a normal offspring, a small proportion of babies will develop active retino-chorditis or mental retardation in childhood or young adulthood. • In immunocompetent adults: flu-like symptoms sometimes associated with lymphadenopathy • In immunocompromised individuals: generalized parasitemia involvement of brain, liver lung and other organs, and often death.

Toxoplasma gondii

Treatment • Acute infections benefit from pyrimethamine or sulphadiazine. • Spiramycin is a successful alternative. • Pregnant women are advised to avoid cat litter and to handle uncooked and undercooked meat carefully.

Toxoplasma gondii

DISEASE: Primary Amebic Meningo-encephalitis HOW ACQUIRED: Diving into contaminated pond water HOW DIAGNOSED: Observation of trophozoites in CSF or cysts in autopsy tissue

Naegleria fowleri

• The treatment of choice for primary amoebic meningoencephalitis (PAM), or infection with brain-eating amoeba (Naegleria fowleri) is the antifungal amphotericin B. • Some survivors in North America were treated with a combination of drugs that included amphotericin B, rifampin, fluconazole and a drug called miltefosine. • Miltefosine is a drug approved for treating leishmaniasis, a parasitic disease that’s spread by sandflies.

Treatment for N. Fowleri