10 Malaria Flashcards
What species is the vector for malaria infections?
Anopheles mosquito (female)
What are the five different malaria species we discussed?
Plasmodium vivax P. falciparum P. malariae P. ovale P. knowlesi
Varied clinical manifestations based on causative species
The reproductive event for malaria species occurs in…
Mosquito saliva
The malaria life cycle has a ____ phase and a ______ phase
Human phase
Mosquito phase
The human phase of the malaria life cycle begins with…
Injection of Plasmodium sporozoites (motile forms) through transmission of mosquito saliva during blood meal
After sporozoites enter the human host, they…
Migrate to liver and asexual division known as schizogony cycle begins
Rapid cell division at this point
Life cycle form released from this phase are called MEROZOITES
______ can infect other liver cells or RBCs
MEROZOITES (the products of schizogony)
This is called the Erythrocytic cycle
Once in RBC, the MEROZOITE enlarges and undergoes a differentiation into a _______ cell termed a ___________.
Uninucleate
Ring Trophozoite
As trophozoites age, they can develop into …
Amoeboid trophozoites
The single nucleus trophozoite can also divide to produce a multinucleated form called a _______.
Schizont
______________ are multinucleated cells that produce ___________.
Erythrocytic schizonts
Erythrocytic merozoites
After infected RBCs rupture (spilling merozoites to invade new cells) _______ begins again or ______ is initiated
Schizogony (asexual)
Gametogony (sexual cycle)
Some merozoites in erythrocytes develop into _______ and do not cause erythrocyte to rupture
Gametocytes (male or female)
Mosquito feeds and takes in gamers that lead to sexual reproduction within the mosquito
Sporozoites produced in the mosquito travel to salivary glands of the mosquito
The malaria organism consumes…
Hemoglobin
Fever and chills of malaria correspond to…
Release of pyrogens waste following rupture of RBCs
Pyrogens travel to hypothalamus and causes an increased thermal set point
Episodes of 1-2 hours of severe shivering and high fever follows
__________ release intensifies malarial symptoms
Tumor necrosis factor (TNF) —> inflammation
What are the SSx of malaria?
Fever Gastric manifestations (N/V/D) Headache Back pain Increased sweating Myalgia Cough ANEMIA (result of RBC destruction) Vasodilation —> hypotension
Untreated malaria cases may progress to …
Coma
Renal failure
Respiratory distress
Death
__________ produces resistance to falciparum malaria
Sickle cell anemia
Thought is that the parasite has difficulty utilizing the abnormal hemoglobin
___________ is a receptor for P. vivax merozoites that many African Americans and most West African’s lack
Duffy antigen (glycoprotein)
Makes them resistant to vivax malaria
In 2010, 1691 cases of malaria were reported in the US. Most were linked to …
Travel to Africa
60% were falciparum, 20% vivax
Central and South America and Asia is mostly _____ malaria
Vivax
Benign Tertian Malaria is caused by…
Plasmodium vivax
Plasmodium vivax tends to infect ________ erythrocytes
Young
Fever and chills in vivax malaria are due to
Rupture of RBC schizonts
Relapses occur with vivax malaria as a result of…
The activation of liver hypnozoites
Can be 3-5 years after initial disease
P. vivax is most prevalent in …
The tropics - Latin America and Caribbean
Rare in US
Rare in West Africa
Vivax malaria accounts for ____% of world wide malaria
43%
How is P. vivax identified
Giemsa stain
Enlarged infected RBCs with SCHUFFNER’S DOTS
What species causes Malignant Tertian Malaria
Plasmodium falciparum
P. falciparum causes __________.
High grade parasitemia - large numbers of parasites in blood
RBCs of any age are affected
P. falciparum is virulent because …
It multiplies rapidly
Fever is very high due to number of parasites
High parasite numbers with P. falciparum can lead to …
Black water fever
High levels of free hemoglobin in urine
Leads to autoimmune reaction in which the host destroys kidney tissue
Chills, fever, rigor, dark to black urine
Falciparum malaria can lead to ____________ obstruction as infected RBCs tend to stick to ________.
Capillary obstruction
Capillary linings
Occlusion of capillaries with parasitized RBCs —> necrosis hemorrhages, extreme fever, mania, convulsions, and death
Cerebral malaria
Frequent vomiting in addition to other malaria symptoms
Gastric falciparum malaria
What is Algid malaria?
Skin is cold but internal temp is high (b/c of lack of BP)
How do you identify P. falciparum?
Erythrocytes with double or multiple ring stages, crescent shaped gametocyte, MAURER’S CLEFTS (not as obvious as Schuffner’s dots)
Young trophozoites and gametocytes (but not schizonts) are observed in periphery
Untreated P. falciparum infections are often…
Fatal
Quartan malaria
Plasmodium malariae
Plasmodium malariae infects _______ erythrocytes
Older
How do you identify P. malariae?
Basket and band shaped trophozoites
Rosette shaped schizonts
Species of plasmodium similar to vivax but common to west Africa
Plasmodium ovale
Zoonotic plasmodium species found in Southeast Asia
Plasmodium knowlesi
May be life-threatening if a heavy parasite burden occurs
How is climate change affecting the fight against malaria?
Thought to change distribution pattern of malaria in the next 50 years
New areas exposed to plasmodium
No host resistance in these areas
Low incidence of vivax malaria in West Africa is due to many _________ persons, but organism is increasingly independent of binding to _______
Duffy negative
Duffy antigen
This is a research topic - potential target for new chemotherapy research
The main mechanism of resistance to malaria treatments is…
Efflux pumps
Leading to multi-drug resistant parasites
Now more expensive to treat and priced out of reach in many countries
Causative agent of Nantucket Island Fever
Babesia microti
NIF aka Babesiosis
What is Babesiosis?
Infects RBCs, presents with malaria-like manifestation
Prevalent in New England in warm months
Vector - deer tick
Babesiosis has no significant rash but does have…
Small pinpoint lesions
Babesiosis is more problematic in what population?
Immunocompromised or asplenic patients
Babesiosis is often a co-infection with…
Lymph disease (because same type of vector)
How do you identify Babesiosis?
Morphology and clinical manifestations similar to P. falciparum (less severe)
Form “CROSS-LIKE” RBCs****
What is the treatment for Babesiosis?
Clindamycin and quinine
Control vectors with insect repellents
What are the three Trypanosomatid diseases?
African sleeping sickness: Trypanosoma brucei
Chagas’ disease: Trypanosoma cruzi
Leishmaniasis: Leishmania spp
Chaga’s disease is also known as…
American trypanosomiasis or American sleeping sickness
Chagas is prevalent in…
Mexico
Central America
South America
In the US, it’s considered a Neglected Parasitic Infection by the CDC
What is the vector for Chagas?
Triatomine bugs (“kissing bugs”)
They like to bite you in the face at night
Causative agent for Chagas’ disease
Trypanosoma cruzi
Parasitic protozoan
What is the life cycle of T. cruzi?
Trypomastigotes passed in feces of triatomine bug (primarily at night)
Trypomastigotes enter cells near inoculation site and differentiate in AMASTIGOTES
Amastigotes replicate by binary fission in cells, different into trypomastigmotes and are released into circulation —> rupture host cells
What are the two stages of Chagas’ disease?
Acute
Chronic
Acute chagas ranges from ______ to ______
Asymptomatic to mild manifestation
Non-specific SSx
May see a CHAGOMA (bite on face)
Most characteristic sign of acute chagas is …
Romaña’s sign (about 1/2 of cases)
Swelling of the eyelid near the parasite entry site or where the organism was rubbed into eye
Chronic chagas may be asymptomatic for years, even for life , but complications include…
Cardiac complications (cardiomyopathy, HF, arrhythmias, sudden death)
Intestinal complications, especially ORGANOMEGALY
Usually have to remove spleen because of intense splenomegaly
Heart complications more common than intestinal complications
How is chagas diagnoses?
Observation of parasite under microscopy
Blood smear in acute phase will show TRYPOMASTIGOTES
Biopsy in chronic cases will show AMASTIGOTES
There are also serological tests and PCR test
How do you treat Chagas?
Antiparasitic
Benznidazole - extremely toxic and not FDA approved; only available through CDC and must monitor kidney and liver functions
