Week 8

Vector Control is not a method used to control the Anopheles mosquito.

False, Vector Control is a strong agent to combat the mosquito that carries Malaria. Mosquito nets alone can help mortality reduce by almost 20%.

What is the reservoir for Malaria?

Humans

Which of these is a reservoir for malaria?

Humans

_______-is responsible for more deaths in children in the world than any other single infectious agent

P. falciparum

In endemic areas, what two groups of people are risk groups for malaria?

Pregnant Women and Infants

What stage are plasmodium parasites in when injected into a human host?

sporozoites

At what stage are Plasmodium in when they are injected in a human?

sporozoite

P. falciparum requires what temperature to survive life cycle (25 days) from midgut to salivary gland?

. 20ºC

PfEMP1 is an adhesive protein that appears on infected erythrocytes to mediate cytoadherence. Based on this, during what stage would it make the most sense for PfEMP1 to be synthesized by the parasite?

. Erythrocytic schizogony

Which of the following is the main parasite for unstable malaria?

. vivax

What are the three species of malaria that infect humans? Describe them.

1. P. falciparum: This is malignant malaria, drug resistance, and deaths due to organ failure. 2. P. vivax, P. ovale: "Benign" relapsing tertian. 3. P. malariae: "Quartan malaria" that if repeated in childhood will lead to nephrotic syndrome due to permanent kidney damage.

What is the correct order for the following stages of the life cycle of Plasmodium falciparum?

1. Transmission to mosquito 2. Merozoite stage 3. Infection 4. Sporozoite 5. Hepatocyte invasion 6. Blood stage 3, 4, 5, 2, 6, 1

What complications can malaria cause in pregnancy? Select all that apply.

A) Abortion B) Anemia C) Low birth weight

What are the effects of malaria on pregnant women?

A. Abortion B. Exacerbated Anemia C. Low Birth Weight

Which of the following is NOT true regarding immunities to malaria?

Asymptomatic adults are not a reservoir for transmission

Female Anopheles, the Malaria vector, bites during what time of the day?

Between dusk and dawn

What is considered the "gold standard" for diagnosis of malaria?

Blood film microscopy examination

Which of the following in the malaria life cycle occurs in mosquitos?

C. Formation of zygote

What protein do red blood cells attach to on vascular endothelial cells and is highly expressed in children?

CD36

Malaria can be confused with all of the following EXCEPT:

Common Cough

Which of the following is true regarding stable malaria?

Epidemics are rare

There is 1 schizont stage in the malaria life cycle in humans

F- there are 2

There is an approved vaccine for malaria in adults.

FALSE, the vaccine is only approved for children.

P. falciparum is not drug resistant, but P. vivax is.

False

In epidemic areas, only pregnant women and infants are risk groups.

False, all age groups are at risk in epidemic areas. In endemic areas, pregnant women and infants are considered the risk groups.

According to the article, in areas of stable transmission, individuals are protected from re-infection due to humoral and cellular immunity. T/F

False, repeated exposure causes individual to be protected from the illness but not the infection, i.e. they are often asymptomatic

The temperature at which P. vivax survives during the life cycle of a mosquito is 20 degrees Celsius.

False, the temperature is lower than 20 degrees Celsius, at approximately 17-18 degrees Celsius. This is significant because this means that P. vivax can survive at lower temperatures than P. falciparum and can thus be transmitted in subtropical and temperate regions, expanding the possible regions of infection.

What component of the hematin molecule is capable of creating free radicals that cause membrane damage?

Fe3+

The oocyst stage of the Plasmodium parasite takes place in the human liver.T/F

Flase. the oocyst stage occurs in the midgut of the mosquito.

Successful parasite transmission from humans to mosquitos is dependent on what sexual precursor cells?

Gametocytes

What cell type do motile sporozoites infect when transmitted into a human by a female anopheline mosquito.

Hepatocyte

Why does malaria cause splenic enlargement in children with stable malaria outbreaks?

Hemolysis caused by the propagation of the falciparum parasite overwhelms the spleen's ability to filter

What is "malaria pigment?"

Hemozoin

Where does the change from gamete to zygote occur in either the infected human or mosquito vector?

In the Midgut of the infected mosquito

Which of the following is not a disease/condition that malaria is commonly confused with?

Infectious mononucleosis

Which of the following is Malaria NOT confused with?

Influenza

What does Glucose-6-Phosphate Dehydrogenase deficiency cause?

It causes a defect in reduction of methemoglobin which affects infected red blood cells. Reply to post from Ricky SolisReply

Which of the following stages of the life cycle is not correct?

Life cycle 11: Mobile fertilized ovum

5% of humans carry abnormal hemoglobin selected often through malaria exposure over multiple generations.

True

Which diseases can malaria be confused with?

Meningitis Acute Respiratory Infection

"Quartan malaria" can cause what if there are repeated childhood infections?

Nephrotic syndrome

Which of the following is the first immobile stage of the malaria parasite life cycle that occurs in the mosquito midgut?

Ookinete

Which of the following Plasmodium species is known to have severe drug resistance?

P. falciparum

Which of the following is the infectious agent responsible for more deaths in children than any other single infectious agent?

P. falciparum

Which species of Plasmodium, which infects humans, is known as "Quartan malaria"?

P. malariae

Which of these is NOT a species of Plasmodium which infects humans throughout the tropics?

P. raveine

What is the main parasite of unstable malaria?

P. vivax

Explain why a vaccine has been difficult to develop against the parasites Plasmodium.

Plasmodium is a eukaryote, which makes it difficult to develop drugs and vaccines that will target the parasite but not human cells. The parasite also changes it's cellular receptors to evade the immune system, again making it difficult to create a specific target.

What region of the Anopheles mosquito becomes occupied by plasmodium sporozoites?

Salivary gland

Which of the following symptoms are associated with severe malaria?

Severe Anaemia Acidosis Pulmonary Oedema Acute Kidney Injury

The disease commonly known as ____________, in heterozygote form, provides significant protection from the malaria parasite.

Sickle Cell Anemia

What happens to P. vivax, P. falciparum, P. ovale, and P. malariae if humans are not available to provide blood-meal?

Since humans are the only reservoir, these mosquito populations will lose their infections within weeks due to the absence of infective humans.

What condition does this child, who lives in a region where malaria transmission is stable, have?

Splenomegaly

Which of the following is true regarding the sporozoite phase of the malaria parasite?

Sporozoites are motile and target human hepatic cells

Which of the following is false regarding Stable and Unstable malaria?

Stable and Unstable malaria are difficult to control.

Which of the following is false regarding the differences between stable and unstable malaria?

The main parasite for the transmission of unstable malaria is plasmodium falciparum.

What is the only reservoir for malaria and why is this the only reservoir?

The only malaria reservoir is human beings because mosquito populations will lose their infections within weeks in the absence of infective humans

Why are Chloroquine phosphate and Quinine sulfate less ideal drug treatments for malaria?

They're less effective due to a high drug resistance rate

Describe the life cycle of the malaria parasite within the mosquito?

When the mosquito ingests infected blood meal, there will typically be male and female gametocytes (haploid) from the malaria parasite, these fuse in the midgut to form a zygote (diploid). Eventually, this zygote turns into a much more mobile form, an ookinete (diploid), which breaks through the midgut wall. The ookinete then forms an oocyst (diploid), which harbors up to one thousand sporozoites. The oocyst then ruptures and when the infected mosquito draws blood meal again, these sporozoites (haploid) are transmitted to another human causing infection; the sporozoites can then turn into merozoites and begin the cycle again.

Malaria is commonly confused with all of the following except:

Zika virus

The host responds to malaria by augmenting splenic immune function and filtrative clearance, accelerating removal of ________.

both parasitized and uninfected erythrocytes

Which of the following is not a reason that malaria infections persist?

dormant parasites may remain in the kidneys for up to 6 years

A Hypnozoite is the___ form of malaria (P. vivax and P. ovale), and can be found in the cells of the ___

dormant; liver

Which species of plasmodium infects humans with malaria throughout the tropics?

falciparum, P. vivax, P. ovale, P. malariae

: Out of the list below, select the indicative clinical features that malaria presents.

fever nausea jaundice

. Asexual and sexual life cycle of malaria parasites are mainly _______.

haploid

Stable malaria has ____ while unstable malaria has ____. Which is not true?

relatively easy control; difficult control

Which of the following stages of the malaria life cycle would NOT be found inside a mosquito?

schizont

Who is chemoprophylaxis recommended for? Select all that apply.

travellers to endemic areas

Which of the following are true of Malaria?

1. Transmitted by the Anopheles mosquito. 2. The RTS, S for Malaria vaccine targets a transcription control protein of P falciparum. 3. Female anopheline mosquitoes transmit malaria during a blood feed by inoculating microscopic motile sporozoites. 4. Sickle cell disease, hemoglobins C and E, ovalocytosis, thalassaemias, and glucose-6-phosphate dehydrogenase (G6PD) deficiency all confer a survival advantage in the presence of malaria. 5. The immune response to Malaria is well studied and thoroughly understood.

In P falciparum malaria, protuberances or knobs emerge on the infected erythrocyte's surface ________ hours after invasion.

12-15 hours

. For up to how many years can the dormant parasites, P. vivax and P. ovale remain in the liver?

5

How is it that certain human beings are innately immune to malaria. Please be sure to reference three different red blood cell disorders within your answer.

5% of humans carry abnormal hemoglobins with changes in the α- or β- globin genes, which have been selected through generations of malaria exposure. Sickled cell hemoglobin, the root cause for sickle cell anemia, can confer resistance for Plasmodium falciparum infections. Glucose-6-phosphate dehydrogenase deficiency which is an X-linked disease causes a defect in reduction of methemoglobin which particularly affects infected RBC, and those hemi or heterozygous for this disease are protected from severe malaria effects. Additional genetic conditions such as ovalcytosis can also confer protection against malaria (specifically cerebral malaria). These genetic red blood cell disorders cause innate immunity and protection against malaria.}

Blood-stage malaria parasites convert ________ (which is released during hemoglobin digestion) into _________.

B. hematin, hemozoin

How many "life cycles" are there in the malaria mosquito vector total?

D. 11

When do female anopheline mosquitoes transmit malaria?

During a blood feed.

Which species of Plasmodium is responsible for more deaths in children in the world than any other single infectious agent?

P. falciparum

Which species of Plasmodium leads to nephrotic syndrome and permanent kidney damage due to repeated childhood infections?

P. malariae

What kind of cells do merozoites infect?

Red Blood Cells

What is the theory that explains why plasmodium undergoes an asexual and a sexual stage within its' life cycle?

Red Queen Theory

What form of Plasmodium is eaten by the mosquito from a human host during a blood meal?

Schizont

Why do schizont red blood cells not appear in blood samples?

Schizont red blood cells express pfEMP1, a protein that binds to CD36 and ICAM1, proteins that are expressed in the walls of blood vessels. This means that schizont cells are bound to the lining of blood vessels (cytoadherence), preventing them from being expressed in blood samples. This serves to avoid detection by the splenic response, which would destroy the host cell. This evasion mechanism can block the blood flow through these vessels, which can block blood flow to the brain leading to death.

According to the Malaria article, which is not a main determinant of the transmission intensity of malaria?

Sugar-feeding behavior of mosquito vector

What is the only reservoir for malaria?

humans

There are two invasive stages of the plasmodium responsible for causing malaria. ____ stage invades liver cells and ____ stage invades red blood cells.

sporozoite, merozoite