70 Questions
What is the stage of Toxoplasma when it is excreted in the feces?
Unsporulated
How many sporozoites are found in each sporocyst?
4
What is the site where the oocyst opens and releases sporozoites in humans or animals?
Duodenum
What is the name of the rapidly multiplying crescentic cells that initiate the acute stage of disease?
Tachyzoites
Where do the sporozoites circulate and invade after passing through the gut wall?
Lymph and blood
What is the duration for which sporulated oocysts can survive in soil?
Several months
What is the phylum of Toxoplasma gondii?
Apicomplexa
Which of the following is NOT a mode of transmission of Toxoplasma gondii?
Through respiratory droplets
What is the definitive host of Toxoplasma gondii?
Members of the cat family (Felidae)
During which stage of Toxoplasma gondii infection do cats acquire the infection through ingestion of oocysts?
Sexual reproduction
What is the role of proteolytic enzymes in the enteric cycle of Toxoplasma gondii?
To dissolve the cyst wall, releasing the bradyzoites
What is the result of the bradyzoites penetrating the epithelial cells of the small intestine?
The formation of numerous asexual generations
What is the primary site of tissue cyst formation in the host?
Brain, liver, and muscles
What is the result of a nonimmune mother being infected during pregnancy?
Congenital toxoplasmosis
What is the effect of tachyzoites on host cells?
They directly destroy cells
What is the consequence of immunosuppressed individuals (such as AIDS patients) being infected with Toxoplasma?
Retinitis or chorioretinitis, encephalitis, pneumonitis
What is the stage of Toxoplasma infection characterized by the formation of tissue cysts in the host?
Chronic stage
What is the result of a cat eating tissue cysts?
All of the above
What is a major cause of blindness and congenital defects due to prenatal toxoplasmosis?
Toxoplasma infection
What is the result of infection during the first trimester of pregnancy?
Stillbirth or major CNS anomalies
Why is avoidance of human contact with cat feces important?
To prevent transmission of Toxoplasma to humans
What is the purpose of periodic serologic screening for IgG and IgM antibodies to Toxoplasma?
To detect the presence of Toxoplasma antibodies in pregnant women
What is the effect of freezing meat at -20°C for 48 hours or heating to 50°C for 4-6 minutes?
Provides sterilization
Which of the following is NOT a method of diagnosing Toxoplasma infection?
Ultrasonography
What is the mode of transmission of Balantidiasis?
Contaminated water or food
What is the role of proteolytic enzymes in the life cycle of Balantidium?
Helping the trophozoite to invade the wall of the colon
What is the characteristic of the micronucleus in the morphology of Balantidium?
It is spherical and located next to the macronucleus
What is the primary site of colonization of trophozoites in the human host?
Large intestine
What is the characteristic of the cyst wall of Balantidium?
It is composed of one or two layers
What is the outcome of most infections with Balantidium coli?
Apparently harmless
What is the primary source of Balantidiasis infection in humans?
Infected water from areas where pigs are raised
What is the location of the micronucleus in the morphology of Balantidium?
Next to the macronucleus, often hidden by it
What is the function of the peristome in the morphology of Balantidium?
It leads to the cytostome, or the mouth
In which part of the host's intestine do the trophozoites colonize?
Large intestine
What is the purpose of proteolytic enzymes in the life cycle of Balantidium?
To facilitate the invasion of the host's intestinal wall
What is the characteristic of the cyst wall of Balantidium?
It is made of one or two layers
In which stage of the life cycle do trophozoites undergo encystation?
In both the large intestine and feces
What is the primary method of transmission of Balantidiasis?
Contaminated food and water
What is the site of initial infection with Balantidium in the host?
Small intestine
What is the result of the trophozoites' invasion of the host's intestinal wall?
They multiply and colonize the host
What is the typical size of the enveloped form of the Herpesvirus?
150-200 nm
What is the primary site of latent infection for HSV-1?
Trigeminal nerve
What is the primary method of transmission of Herpesvirus?
Direct contact
What is the characteristic of the tegument in the Herpesvirus structure?
Asymmetric and amorphous
What is the primary cause of sporadic encephalitis in children in the United States?
HSV-1
What is the result of HSV-1 infection in immunosuppressed hosts?
Frequent reactivation
Which of the following viruses can infect humans and cause severe neurologic disease?
Herpes B virus
What is the primary mode of transmission of HSV-1?
Through infected saliva
What is the duration of the HSV growth cycle?
8-16 hours
What is the laboratory method used to diagnose HSV infections?
Polymerase Chain Reaction (PCR)
What is the characteristic of HSV infections in humans?
They are widespread and usually asymptomatic
What is the outcome of primary HSV infections in most individuals?
They are usually inapparent but result in antibody production
What is the preferred method for rapid diagnostic procedures of Varicella-zoster virus?
PCR assays
What is the characteristic of skin lesions in both herpes zoster and chickenpox?
Multinucleated giant cells with eosinophilic cytoplasmic inclusion bodies
What is the difference between the rash of herpes zoster and chickenpox?
The rash of herpes zoster is restricted to one area of the skin on one side of the body
What is the mode of spread of virus to the skin in herpes zoster?
Intraneural spread
What is the characteristic of the lesions of herpes zoster?
Closely grouped vesicles on an erythematous base
What is an effective therapy for varicella?
Acyclovir, Valacyclovir, Famciclovir, and Foscarnet
In which cells does cytomegalovirus replicate and persist?
Epithelial cells and lymphocytes
What is the incubation period of cytomegalovirus?
4-8 weeks
What is a common consequence of congenital cytomegalovirus infection?
Mental retardation
What is the characteristic of cytomegalovirus among human herpesviruses?
Largest genetic content
In which type of hosts are primary cytomegalovirus infections more severe?
Immunosuppressed hosts
What is the result of cytomegalovirus infection in newborns?
Cytomegalic inclusion disease
What is the primary mode of transmission of Human Herpesvirus 6?
Via oral secretions
What is the typical age of infection for Human Herpesvirus 6?
Early infancy and childhood
What is the disease caused by primary infection with Human Herpesvirus 6?
Roseola infantum
What is the site of persistent infection for Human Herpesvirus 7?
Salivary glands
Which subfamily do Herpesvirus 5, 6, and 7 belong to?
Beta subfamily
What is the treatment for Human Herpesvirus?
Acyclovir
Test your knowledge on Toxoplasma and Balantidium, two important parasites in microbiology. Learn about their characteristics, transmission, and hosts. Perfect for students of microbiology and parasitology!
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