Malaria: Infection and Symptoms

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Questions and Answers

What is the main infectious form of Plasmodium introduced into humans by mosquitoes?

Trophozoites

Sporozoites (correct)

Merozoites

Gametocytes

Which species of Plasmodium is associated with benign quartan malaria?

P.ovale

P.vivax

P.malariae (correct)

P.falciparum

What is the correct term for the stage of malaria infection that occurs in the liver before invading red blood cells?

Gametogony

Pre-erythrocytic schizogony

Exoerythrocytic stage (correct)

Erythrocytic schizogony

Which of the following is NOT a form of transmission for Plasmodium species?

Inhalation of spores Signup and view all the answers

What is a characteristic of P.falciparum malaria?

Exhibits a fever periodicity of 48 hours Signup and view all the answers

How long do sporozoites remain in circulation before entering the liver?

30 minutes Signup and view all the answers

What hosts are primarily affected by the various Plasmodium species?

A wide range of birds, reptiles, and mammals Signup and view all the answers

What is the periodicity of fever for P.knowlesi infections?

Once a day Signup and view all the answers

What is the primary method through which P.falciparum sequesters parasites in the body?

Cytoadherence of infected erythrocytes Signup and view all the answers

Which of the following is characteristic of benign malaria?

Milder symptoms with specific fever patterns Signup and view all the answers

What is the treatment of choice for P.knowlesi infection?

Primaquine Signup and view all the answers

How does the cycling of fever typically manifest in P.malariae infection?

Every fourth day Signup and view all the answers

What role does the PfEMP-1 antigen play in the pathogenesis of P.falciparum?

Facilitates sequestration of parasites Signup and view all the answers

What adverse condition can result from the sequestration of parasites in organs by P.falciparum?

Congestion and hypoxia Signup and view all the answers

Which species of malaria is specifically noted for having no rapid diagnostic tests available?

P.knowlesi Signup and view all the answers

What phenomenon involves the binding of infected RBCs to uninfected RBCs in P.falciparum infections?

Rosetting Signup and view all the answers

What is a common clinical feature of P. knowlesi infection?

Paroxysms of fever occurring daily Signup and view all the answers

How does P. knowlesi infection cause anemia in patients?

Destruction of both infected and uninfected RBCs Signup and view all the answers

Which of the following is a key difference in malarial presentation between P. falciparum and P. vivax?

P. falciparum causes more severe malaria than P. vivax Signup and view all the answers

What morphological feature can be seen in blood smears of patients infected with P. knowlesi?

Early trophozoites indistinguishable from P. falciparum Signup and view all the answers

Which complication is most frequently associated with P. knowlesi infection?

Respiratory distress Signup and view all the answers

What characterizes algid malaria?

Cold clammy skin and profound shock Signup and view all the answers

What leads to splenomegaly in patients with P. knowlesi infection?

Massive proliferation of macrophages engulfing coated RBCs Signup and view all the answers

What is the characteristic RBC cycle length for P. knowlesi that affects its clinical presentation?

24 hours Signup and view all the answers

Which statement correctly describes septicemic malaria?

It leads to multiorgan failure with high-grade fever. Signup and view all the answers

What is a typical outcome of severe falciparum malaria in adults?

Noncardiogenic pulmonary edema with high mortality. Signup and view all the answers

What is a notable lack in the clinical features of P. knowlesi malaria compared to other types of malaria?

Lack of cerebral malaria Signup and view all the answers

In cases of malaria transmitted via blood transfusion, which of the following is true?

Incubation period is often short. Signup and view all the answers

What effect does malaria have on pregnancy?

It increases the risk of fetal distress and low birth weight. Signup and view all the answers

Which of the following complications can arise from malaria in children?

Hypoglycemia associated with poor prognosis Signup and view all the answers

The management of transfusion malaria cases is similar to what other type of malaria infections?

Naturally acquired infections Signup and view all the answers

Which statement is true regarding the treatment for transfusion malaria?

It typically does not involve relapse. Signup and view all the answers

What does a colored band at only test line 1 indicate?

P. falciparum infection Signup and view all the answers

Which of the following malarial antigens can be detected by rapid diagnostic tests?

Parasite lactate dehydrogenase Signup and view all the answers

Why is the control line important in rapid diagnostic tests?

It confirms the test is valid. Signup and view all the answers

Which statement about parasite aldolase is true?

It is produced by all Plasmodium species. Signup and view all the answers

What is a limitation of rapid diagnostic tests for malaria?

They cannot differentiate all Plasmodium species. Signup and view all the answers

How does a rapid diagnostic test identify infections?

By detecting malarial antigens. Signup and view all the answers

What advantage do rapid diagnostic tests offer for malaria diagnosis?

Require no special equipment or trained personnel. Signup and view all the answers

What does the presence of bands at both test lines 1 and 2 indicate?

Presence of mixed infection Signup and view all the answers

Study Notes

Malaria

Malaria is a disease caused by the Plasmodium parasite, transmitted by infected mosquitoes
The infectious agent is the sporozoite
Most commonly spread through mosquito bites, but transmission is also possible through blood transfusion or transplacentally.

Malaria in Humans

In humans, the parasite goes through three distinct stages: pre-erythrocytic schizogony, erythrocytic schizogony, and gametogony.
There are five species of Plasmodium that infect humans:
- P. vivax
- P. falciparum
- P. malariae
- P. ovale
- P. knowlesi
Each species has different patterns of fever and severity.

P. knowlesi Infection

P. knowlesi causes quotidian malaria, with fever recurring daily.
Quotidian malaria is caused by a shorter red blood cell cycle (24 hours)
Clinical features resemble P. vivax infection, but P. knowlesi is associated with more severe disease.
P. knowlesi infections are increasingly reported in Southeast Asia.
The only reported case in India is from the Andaman Islands.

Clinical Features of Malaria

Benign Malaria is milder, caused by all four species except P. falciparum.
Benign Malaria symptoms include:
- Febrile paroxysm, a cycle of chills, fever, and sweating that occurs intermittently
- Anemia (normocytic normochromic anemia)
- Splenomegaly
**Malignant Tertian Malaria (caused by P. falciparum) ** is characterized by sequestration of infected red blood cells in deep visceral organs.
Malignant Tertian Malaria clinical features include:
- Severe anemia
- Prostration
- Headache
- Nausea
- Algid malaria, characterized by cold clammy skin, hypotension, peripheral circulatory failure and profound shock.
- Septicemic malaria, characterized by high-grade fever with dissemination of the parasite to various organs which can lead to multiorgan failure.
- Pulmonary edema and adult respiratory distress syndrome
- Hypoglycemia
- Renal failure

Pathogenesis of P. falciparum Malaria

Cytoadherence: Infected red blood cells adhere to the lining of blood vessels in the brain, kidney, etc.
Rosetting: Infected red blood cells bind to uninfected red blood cells, helping to avoid detection by the spleen.

Diagnosing Malaria

Blood smear examination: This is the gold standard for diagnosing malaria and can be used to differentiate between species.
Rapid Diagnostic Tests (RDTs) : RDTs are fast, easy to use, and can detect specific Plasmodium antigens.
- RDTs use nitrocellulose membrane strips with multiple test lines and a control line.
- RDTs can differentiate between infections by P. falciparum and other species.
PCR assays: PCR assays are used to detect specific P. knowlesi DNA.

Treatment of Malaria

Chloroquine and primaquine: Used to treat uncomplicated malaria
Prompt treatment is crucial, especially for P. knowlesi infections.

Malaria in Special Situations

Transfusion Malaria: Occurs when malaria parasites are transmitted through blood transfusion, needle stick injury, or organ transplantation.
- The infective form can be merozoites, trophozoites, or schizonts.
- No pre-erythrocytic stage or relapse.
- Treatment is the same as for naturally acquired infections.
Malaria in Pregnancy: Pregnant women are at greater risk of severe malaria.
- Can cause fetal distress, premature birth, low birth weight, and stillbirth.
- Pregnant women are prone to severe anemia, hypoglycemia, and acute pulmonary edema.

Disadvantages of Rapid Diagnostic Tests (RDTs)

Relatively expensive.
Less specific than blood smear examinations.
Difficult to differentiate between species.

Advantages of Rapid Diagnostic Tests (RDTs)

Fast and easy to use.
Do not require trained microscopists or specialized equipment.l

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Description

This quiz covers essential information about malaria, including its causes, transmission methods, and the stages of infection by the Plasmodium parasite. It focuses on the different species that infect humans, particularly P. knowlesi, along with their clinical features and severity.