Malaria and Snail Fever Overview

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Questions and Answers

What characteristic of the human threadworm allows it to auto-infect its hosts?

It regurgitates microbes throughout the host's tissues. (correct)

It maintains multiple generations.

It lays eggs in the soil.

It requires an intermediate host for infection.

What is the primary mode of transmission for human threadworm infections?

Ingestion of contaminated food.

Airborne transmission.

Vector-borne transmission.

Direct penetration through the skin. (correct)

What is a significant avoidance tactic for preventing human threadworm infections?

Consuming well-cooked food.

Wearing shoes to protect against infected soil. (correct)

Regular hand washing.

Avoiding contact with animals.

Which of the following is true regarding the life cycle of the trichina worm?

Adults and juveniles develop within different tissues in the definitive host. Signup and view all the answers

What symptom is commonly associated with human threadworm infections?

Typically asymptomatic. Signup and view all the answers

What is the primary mode of transmission for malaria?

Biological vector through mosquito bites Signup and view all the answers

Which organ or tissue does malaria primarily infect in humans?

Red blood cells Signup and view all the answers

Which of the following is true regarding human schistosomiasis?

Snails are the only first intermediate hosts involved Signup and view all the answers

What type of organism causes malaria?

Protozoan Signup and view all the answers

What is the estimated worldwide prevalence of human schistosomiasis?

82 million people Signup and view all the answers

Which method is NOT a primary avoidance tactic for schistosomiasis?

Using bugspray Signup and view all the answers

What type of immunity can develop in individuals living in endemic areas of malaria?

Premunition Signup and view all the answers

What is the definitive host for schistosomiasis?

Human Signup and view all the answers

What is the primary avoidance tactic for preventing trichinosis?

Ensure meat is cooked thoroughly Signup and view all the answers

Which organisms serve as definitive and intermediate hosts for trichinosis?

Pigs and rats Signup and view all the answers

What organ or tissue is primarily infected by the trichina worm?

Small intestine Signup and view all the answers

Which symptom is commonly associated with trichinosis?

Fever Signup and view all the answers

What common symptom is associated with chronic giant intestinal roundworm infections in children?

Impaired weight gain Signup and view all the answers

What may happen in severe cases of whipworm infections?

Rectal prolapse Signup and view all the answers

How can hookworm infections be primarily contracted?

By walking barefoot on contaminated soil Signup and view all the answers

What is the recommended method for diagnosing whipworm infections?

Stool microscopy Signup and view all the answers

What is the primary mode of transmission for whipworm infections?

Fecal/oral and direct penetration Signup and view all the answers

Which of the following organs are mainly infected by whipworms?

Small intestine and large intestine Signup and view all the answers

How can the spread of freshwater ich be effectively prevented?

Manage water temperature and quarantine new fish Signup and view all the answers

Which symptom is NOT commonly associated with whipworm infection?

Itching and red spots Signup and view all the answers

Which preventive measure is recommended for avoiding crypto disease?

Avoid untreated water and maintain hygiene Signup and view all the answers

What is a notable treatment option for freshwater ich?

Copper sulfate Signup and view all the answers

Public lice primarily spread through which of the following?

Sexual contact and shared bedding Signup and view all the answers

What type of organism causes whipworm infections?

Parasitic worms (Nematodes) Signup and view all the answers

Study Notes

Malaria

Caused by 5 species of protozoa
Protozoa have a complex indirect life cycle
Anopheles mosquitoes are vectors and definitive hosts
Malaria is horizontally transmitted by blood transfusions
Malaria is vertically transmitted via sequestration of parasites in the placenta
Common in sub-Saharan Africa, previously worldwide
Immunity (premunition) can develop in endemic areas
Emerging vaccines and antimalarial drugs exist
Symptoms typically develop 10-15 days after infected mosquito bite; can be delayed months
Causal Agent: Plasmodium Falciparum
Type of Organism: Protozoan
Most Prevalent Region: Sub-Saharan Africa
Transmission: Biological Vector
Definitive Hosts: Mosquitoes
Intermediate Hosts: Humans, Primates
Infected Tissues/Organs: Red blood cells
Symptoms: Fever, chills
Primary Avoidance: Prophylaxis, bugspray

Snail Fever (Human Schistosomiasis)

Caused by flukes
Transmission in humans is by direct penetration
Complex life cycle with snails as intermediate hosts
Most infections in sub-Saharan Africa
Estimated global prevalence of 82 million people
Humans can develop immunity
Some species cause swimmer's itch, a non-contagious Michigan disease
Causal Agent: Schistosomes
Type of Organism: Fluke
Most Prevalent Region: Africa and Brazil
Transmission: Direct penetration
Definitive Hosts: Humans
Intermediate Hosts: Freshwater snails
Infected Tissues/Organs: Liver, bladder
Symptoms: Fever, chills, headache, itching
Primary Avoidance: Stay out of water with schistosomes

Human Threadworm Disease (Strongyloidiasis)

Caused by human threadworm
Type of Organism: Nematode
Most Prevalent Region: Tropical and subtropical areas
Transmission: Direct penetration
Definitive Hosts: Humans
Intermediate Hosts: None
Infected Tissues/Organs: Large intestine
Symptoms: None
Primary Avoidance: Avoid infected soil, wear shoes

Trichinosis

Caused by a nematode (trichina worm)
Transmission is trophic
Simple (direct) life cycle, unusual as definitive hosts serve as intermediate hosts
Muscle cells are invaded causing myofibrils to break down; juveniles are encapsulated
Capillary network surrounds muscle cell, creating a nurse cell
Common worldwide
Man is an accidental host, primarily through consuming infected carnivore meat
Causal Agent: Trichina worm
Type of Organism: Nematode
Most Prevalent Region: Cosmopolitan
Transmission: Trophic
Definitive Hosts: Pigs, rats
Intermediate Hosts: Pigs, rats
Infected Tissues/Organs: Small intestine and striated muscle cells
Symptoms: Fever
Primary Avoidance: Don't eat undercooked meat, especially game

Hookworms

2017 study found 34% of participants suffering from hookworm, a parasitic infection contracted by walking barefoot on contaminated soil or fecal matter
Hookworms are species-specific; cannot be identified just by eggs
Can cause cutaneous larva migrans (ground itch) in humans, but mature in other animals
Live in small intestine, attached to villi and feed on blood and tissue
Severe infections: up to 200mL of blood loss per day
Causal Agent: Hookworms
Type of Organism: Parasites
Most Prevalent Region: Worldwide
Transmission: Fecal-oral, and direct penetration
Definitive Hosts: Humans
Intermediate Hosts: None
Infected Tissues/Organs: Small intestine, attached to villi (feed on blood and tissue)

Giant Intestinal Roundworms

Trypsin (proteolytic enzyme) breaks down proteins in small intestine. Worms excrete anti-trypsin
Symptoms: appetite loss, impaired weight gain, growth/cognitive impairment,
Can cause difficulty breathing and fever as larvae migrate through the lungs, or abdominal discomfort, distension, nausea, and diarrhea when adults settle in the small intestine.

Whipworms

Human whipworm causes constant urge to defecate, sometimes with prolapse
Diagnosed by finding eggs in stool sample
Eggs can be hard to find in light infections; a concentration procedure is recommended
Prevention: Avoid ingesting soil with human feces. Wash hands, wash, peel, or cook vegetables before eating
Causal Agent: Parasitic worms
Type of Organism: Nematodes
Most Prevalent Region: Subtropical/tropical climates
Transmission: Fecal-oral, and direct penetration
Definitive Hosts: Humans, Intermediate hosts: None

Freshwater Ich (white spot disease)

Protozoan parasite causing "white spot disease" in freshwater fish
Highly contagious, obligate parasite
Life cycle: Trophont (attaches to fish; resistant to treatment), Tomont (develops in cysts; not treatable), Theront (free-swimming and treatable stage)
Symptoms: White spots, lethargy, gasping, and sudden death
Treatments: Copper sulfate and formalin, Regular dosing to target theronts; removal of debris and dead fish
Prevention: Quarantine new fish, maintain water temperature, reduce stress

Crypto Disease

Waterborne protozoan causing cryptosporidiosis
Protozoan life cycle: Oocysts that survive outside the host and are resistant to disinfectants.
Transmission: Fecal-oral route, contaminated water/food, or direct contact
Symptoms: Watery diarrhea, dehydration, nausea; severe in immunocompromised
Treatment: Rehydration therapy, Nitazoxanide (less effective in immunocompromised) - Prevention: Avoiding untreated water, maintaining hygiene, and boiling water if suspected contamination

Pubic Lice (Pediculosis)

Primitive parasite infecting coarse hair, spread primarily via direct, sexual contact
Life cycle: Egg(Nit)- hatches in 6-10 days. Nymph- feeds on blood, matures in 2-3 weeks; and Adults - lives 3-4 weeks, dies without a host in 24-48 hours.
Symptoms: Itching, small red/blue spots, yellow/white dots on hair, crusty eyelashes.
Treatments: Over-the-counter lotions (permethrin, pyrethrins). Hair removal ineffective.
Prevention: Practice safe sex, avoid sharing bedding or clothing
Habitat: Found worldwide; infects humans only.

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Description

Explore the key aspects of Malaria and Snail Fever, including their causes, transmission methods, and prevalent regions. Understand the life cycles of the parasites involved and the symptoms associated with these diseases. This quiz provides insights into prevention and current medical advancements.