Malaria, Other Blood Parasites, and Parasites that Cause Anemia

Describe some stain characteristics of Babesiosi.

"Maltese-cross", just ring trophs. Pleomorphic, no gametocytes, intra- and extra-cellular. No TI/T2 Agn. Serology and PCR also used to diagnose

Describe the process of the thin film method

1. A push film is made from a drop of blood 2. Cells are fixed prior to staining a preserve red cell morphology 3. Slide is stained with Giemsa 4. Entire slide is screened at 10x to look for Microfilaria At least 300 fields of the slide is screened under oil 100x: identify parasites, and then if they are intra- or extra-cellular

Describe the thick film method of detection.

1. Blood is obtained by finger stick or phebotomy 2. Defibrinated 3. Air-dried at least 2 hours or over night 4. Unfixed cells are lysed during Giemsa staining

What are febrile symptoms of Classical Uncomplicated Malaria?

1. Cold stage (shivering) 2. Hot stage (fever, headache, nausea, seizures in kids) 3. Sweating stage (sweats, extreme tiredness, return to normal temperature) Length of febrile symptoms is 6-10 hours, then Fever cycle is established

Out of the 1724 malaria cases reported in 2014, how many were imported? Congenital? Cryptic? Severe? Fatal?

1688 imported 1 congenital 2 cryptic 17% classified as severe 5 resulted in death

Describe the epidemiology of Malaria

198-214 million new cases world wide. Half of the world's population is at risk for infection. Fifth most frequent cause of infectious disease-releated deaths. 438,000-584,000 deaths, ~90% occurring in Africa

What region-traveled had the highest percentage of imported malaria to the US?

Africa (84.3%), followed next by Asia (9.8%)

What are some stain characteristics of P. malariae/P. knowlesi?

All stages are present. Thick rings, <1/3 size RBC. Basket, band forms with rosette schizonts. Parasitemia low for P. malariae. Parasitemia high for P. knowlesi

What are some stain characteristics of P. ovale?

All stages present, trophs more compact. >1/3 size RBC (enlarged). 1/3 oval shape, fimbriated edges Parasitemia low

What are some stain characteristics of P. vivax?

All stages present. Ameboid trophs. >1/3 size RBC (enlarged). Schizont with >12 merozoites. Parasitemia low

What are the clinically significant Trypanosomiasis?

American Trypanosomiasis: Trypanosoma cruzi (South America) African Trypanosomiasis: Trypanosoma brucei gambiense (West Africa), Trypanosoma brucei rhodesiense (East Africa)

Briefly describe the human life cycle of Trypanosoma cruzi.

An infected triatomine insect vector (or "kissing" bug) takes a blood meal and releases trypomastigotes in its feces near the site of the bite wound. Trypomastigotes enter the host through the wound or through intact mucosal membranes, such as the conjunctiva. Inside the host, the trypomastigotes invade cells near the site of inoculation, where they differentiate into intracellular amastigotes. These multiply by binary fission and differentiate into trypomastigotes, and then are released into the circulation as bloodstream. Trypomastigotes infect cells from a variety of tissues and transform into intracellular amastigotes in new infection sites. Clinical manifestations can result from this infective cycle. The bloodstream trypomastigotes do not replicate. Replication resumes only when the parasites enter another cell or are ingested by another vector.

Describe Severe Malaria (not symptoms).

Associated with high levels of parasitemia (>5%), usually seen with P. falciparum Often first infection (young, lack of antibodies) Linked to infected RBC sticking in microvasculature, and brisk hemolytic anemia

How is Loa loa transmitted?

By deer fly

What is an additional drawback to Babesiosi?

Currently no FDA-approved screening serology or PCR available for Blood Product testing

What are some examples of personal protection from mosquitoes (malaria prevention)?

DEET repellant; body coverage with clothes, particularly after dusk when the mosquitoes are out; sleep under mosquito netting; close windows at night and sleep above the 3rd floor level

Describe the Fever cycle found in Classical Uncomplicated Malaria

Depends on the malaria. Tertian (every other day): P. falciparum, vivax, and ovale Quatern (every 3rd day): P. malariae

Describe some stain characteristics of T. brucei gambiense and T. brucei rhodesiense.

Diagnosis based on thick and thin films Trypomastigotes are seen in the blood, lymph node aspirate, or CSF. Extra-erythrocytic, long (14-33 uM). Small, terminal kinetoplast. Markedly undulating membrane, dividing forms often seen

Briefly describe the human life cycle of African Trypanosomiasis.

During a blood meal on the mammalian host, an infected tsetse fly (genus Glossina) injects metacyclic trypomastigotes into skin tissue. The parasites enter the lymphatic system and pass into the bloodstream. Inside the host, they transform into bloodstream trypomastigotes, are carried to other sites throughout the body, reach other blood fluids (e.g., lymph, spinal fluid), and continue the replication by binary fission. The entire life cycle of African Trypanosomes is represented by extracellular stages.

Briefly describe the life cycle of Onchocerciasis

During a blood meal, an infected blackfly introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound In subcutaneous tissues the larvae develop into adult filariae, which commonly reside in nodules in subcutaneous connective tissues, where female worms are capable of reproducing. They are occasionally found in peripheral blood, urine, and sputum but are typically found in the skin and in the lymphatics of connective tissues. A blackfly ingests the microfilariae during a blood meal. After ingestion, the microfilariae migrate from the gut to the thoracic muscles. There the microfilariae develop into third-stage infective larvae. The third-stage infective larvae migrate to the blackfly's proboscis and can infect another human when the fly takes a blood meal.

Briefly describe the life cycle of Loa loa (African Eye Worm)

During a blood meal, an infected fly introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound. The larvae develop into adults that commonly reside in subcutaneous tissue, and produce microfilariae which are sheathed and have diurnal periodicity. During the day they are found in peripheral blood, but during the noncirculation phase, they are found in the lungs. The fly ingests microfilariae during a blood meal. After ingestion, the microfilariae lose their sheaths and migrate from the fly's midgut to the thoracic muscles of the arthropod. There the microfilariae develop into third-stage infective larvae These larvae migrate to the fly's proboscis and can infect another human when the fly takes a blood meal.

Briefly describe the life cycle of Schistosome Flukes.

Eggs are eliminated with feces or urine. Under optimal conditions the eggs hatch and release miracidia, which swim and penetrate specific snail intermediate hosts. The stages in the snail generations of sporocysts and the production of cercariae. Upon release from the snail, the infective cercariae swim, penetrate the skin of the human host, and shed their forked tail, becoming schistosomulae. The schistosomulae migrate through several tissues and stages to their residence in the veins The females deposit eggs in the small venules of the portal and perivesical systems. The eggs are moved progressively toward the GI tract and are eliminated with feces or urine.

What are some benefits to using thin film method of diagnosis?

Excellent for speciating Malaia and is fast, it is the first slide available for review Good to also ID Babesia, Trypanosomes, and Microfiliarial

True or false: serology is often used to diagnose T gambiense and T rhodesiense

False, serology is not useful

Describe the symptoms of Babesiosis (if symptomatic)

Febrile illness: onset 1-4 weeks after exposure. Fever, chills, sweating with no specific cycles, Myalgias, Fatigue, Hemolytic anemia, Splenomegaly

Describe the symptoms found in Common Uncomplicated Malaria

Flu-like symptoms: chills, fever, increased heart rate, increased respiratory rate, general malaise Symptoms related to hemolytic anemia: weakness, mild jaundice, splenomegaly Tender hepatomegaly Nausea/vomiting/diarrhea/abdominal pain

What is type of organism is Trypanosomiasis?

Hemoflagellates with blood and tissue phases

What is malaria?

Human disease caused by one of 5 Plasmodium parasites.

Where are the most severe cases of Babesiosi seen?

In the immunosuppressed, Splenectomized, Elderly (>50yo), transfusion transmitted cases (20% death rate reported)

Briefly describe the human life cycle of Babesiosis.

Infected tick bites a human for a blood meal, Babesia sporozoites are introduced. Sporozoites then go into erythrocytes, where they asexually reproduce by budding. The parasites multiply within the blood; the disease begins to clinically manifest itself. Once within the human, the parasite cycle cannot continue, and is only transmitted human-to-human by blood transfusions

What are the acute symptoms of Schistosomal Disease?

Initially asymptomatic. Within days, itchy skin/rash. 1-2 months: fever, chills, couch, muscle aches (Katayama fever)

Review these slides showing thick and thin films.

Left-thick, right-thin

Small proportion of patients with lymphatic filariasis infections may develop:

Lymphedema in dependent sites due to lymphatic drainage failure (legs, scrotum, less often arms and breasts) Elephantiasis with thickening and hardening of the skin Pulmonary Eosinophilic syndrome

What is the typical graph of imported malaria cases by month?

Majority of cases occur in the summer (following vacations), small spike in January (holiday traveling)

Malaria is most commonly seen between ________ to _____ latitudes and below _______ of altitude

Malaria is most commonly seen between *45N* to *40S* and below *1800m* of altitude

Briefly describe the Mosquito/Sporongonic cycle of malaria.

Mosquito takes a blood meal and ingests gametocytes, which becomes gets a tail to become a microgametocyte. This enters a macrogamete, which then develops into an Ookinete and then to an Oocyst. The oocyst ruptures and releases sporozoites, which are injected when the mosquito takes a blood meal

When are Microfilaria most active? What is this significance?

Most active at night (8p), so blood tests should be drawn at that time

What are some disease manifestations of Loa loa (African Eye Worm)?

Most are asymptomatic, infection is chronic (<17 yrs). Calabar swelling transient, non-tender swelling on arms and legs near joints. Eye worm - adult migrates across eye (<1 day). Microfilaria in blood 10a-2p. See eosinophilia. Have hives, itching, muscle pains, joint pain, tiredness. *does not cause blindness*

Describe Acute Chagas Disease.

Most cases are asymptomatic. If symptomatic: Fever, fatigue, body and headache, rash, swelling of facial tissue/eyelid at site of bite (Romana's sign), death may occur from acute myocarditis or acute meningoencephalitis

Describe some general characteristics of lymphatic filariasis infections.

Most often caused by nemotodes that live in lymphatics and transmitted by mosquitoes. Most infections are asymptomatic but chronic, often associated with eosinophilia

What is unique about presentation of malaria in US vs elsewhere?

Most patients will present with flu-like symptoms before fever cycle has been established

How are Microfilarial infections diagnosed?

Nodules containing adult worms may be detected on biopsy Microfilaria may be detected in skin snips (Oncocerca volvulus) or in peripheral blood (Brugia malayi, Wucheria bancrofti, and Loa loa) Serology may be available from reference labs

What is a downside to using thin film for diagnosis?

Not as sensitive as the thick film

Describe Chronic Chagas Disease

Occurs after long period (decades) of asymptomatic infection. Cardiac complications: dilated cardiomyopathy, heart failure, dysrhythmias, cardiac arrest Intestinal complications: mega-esophagus leading to difficulties swallowing, megacolon leading to difficulties passing stool

Briefly describe the bug life cycle of Trypanosoma cruzi.

Occurs in the *Triatomine bug*. The "kissing" bug becomes infected by feeding on human or animal blood that contains circulating parasites. The ingested trypomastigotes transform into epimastigotes in the vector's midgut. The parasites multiply and differentiate in the midgut, and differentiate into infective metacyclic trypomastigotes in the hindgut.

Briefly describe the bug life cycle of African Trypanosomiasis.

Occurs in the *Tsetse fly*. The tsetse fly becomes infected with bloodstream trypomastigotes when taking a blood meal on an infected mammalian host. In the fly's midgut, the parasites transform into procyclic trypomastigotes, multiply by binary fission, leave the midgut, and transform into epimastigotes. These reach the fly's salivary glands and continue multiplication by binary fission. The cycle in the fly takes approximately 3 weeks.

What strain is most likely to present first in a Dual infection? Vs. second infection?

P. falciparum is usually the malaria initially treated. Then, weeks/months later, P. vivax or P. ovale reactivates (was not treated with drug given for P. falciparum) and emerges to cause a relapse in febrile disease

Describe the breakdown % of occurrence for different strains of malaria

P. falciparum most common (66.1%), then some P. vivax (13.3%), P. ovale (5.2%), and P. malariae (2.7%) 11.7% were undetermined, and <1% patients with mixed infections

What malaria exists in tropical to more temperate climates (including South & Central America, SE Asia, and Indonesia) and is relatively absent from Africa?

P. vivax

What is different about the presentation of and P. falciparum and P. malariae vs P. vivax and P. ovale?

P. vivax and P. ovale sometimes had a longer presentation (i.e. some patients were infected a year or more before being seen) Most P. falciparum patients presented within 30 days (82%); many P. malariae presented within 30 days as well (46.9)

Name the 5 Plasmodium parasites that cause Malaria.

Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, Plasmodium knowlesi

What are some stain characteristics of P. falciparum?

Rings or gametocytes are predominate, small delicate rings. <1/3 size RBC. Headphone and applique forms. Multiple rings/RBC. Banana-shaped gametocytes. Usually a high parasitemia.

How is chronic chagas disease diagnosed?

Serology for diagnosis and screening of the blood supply PCR may be used on blood Amastigotes are seen in cardiac, esophageal, and colonic muscle

What is the disease manifestation like for T. gambiense?

T. gambiense is West African Sleeping Sickness Stage 1 occurs 1-2 months after infection: mild fever, headache, muscle & joint pain, itchy skin, malaise, swollen lymph nodes, and weight loss Stage 2 occurs 1-2 years after initial infection: personality changes, confusion, sleepiness, death in 3-7 years after initial infection

What is the disease manifestation like for T. rhodesiense?

T. rhodesiense is East African Sleeping Sickness Stage 1 occurs 1-2 weeks after infection: large sore forms at the site of bite. Fever, headache, muscle & joint pain, enlarged lymph nodes, rash sometimes seen. Organism detect in blood Stage 2 occurs 1-2 months after infection: Disease enters CNS --> Coma and death if not Rx

What are some cons to serology TAT?

Takes more than a week for results, often provides misleading information for diagnosis

What venous systems do Schistosoma mansoni worms target?

Target superior mesenteric veins draining colon

What venous systems do Schistosoma japonicum worms target?

Target superior mesenteric veins of small bowel

What venous systems do Schistosoma hematobium worms target?

Target veins draining bladder and rectum

Briefly describe the tick life cycle of Babesiosis.

The gametes are once again ingested, where they join and undergo the sporogonic, producing sporozoites. Vertical transmission occurs in some types of Babesia, but not B. microti.

Describe the epidemiology of Schistosome flukes.

These are blood flukes, have two sexes, and spined or knobbed eggs. Snail is intermediate host, Human is infected percutaneously, wading/swimming in infested fresh water sources

How is acute infection of chagas disease diagnosed?

Thick and thin blood film T. cruzi trypomastigotes in blood: extra-erythrocytic, "C" and "S" shaped, simple undulating membrane, large subterminal kinetoplast PCR for diagnosis available from reference labs

Describe some general characteristics of Onchocerciasis.

Transmitted by black flies Larv ae wander slowly, growing near point of inoculation into worm nodules Microfilaria are released and wander in skin, NOT BLOOD. This leads to: papular dermatitis, and microfilaria migrating to eyes and host response to dead MF produces keratitis, destruction of cornea, retinal, and optical nerve inflammation --> *blindness*

Briefly describe the human cycle of malaria

Two stages: *Exo-erythrocytic* cycle: sporozoite ends up in liver cell and becomes a schizont. When schizont ruptures, --> *Erythrocytic cycle*: Sporozoite from ruptured schizont enters RBC (immature trophozoite). Some mature, become a schizont, rupture, and repeat cycle. Other trophozoites become gametocytes to go through asexual reproduction and be taken up by a mosquito (as they take a blood meal)

Describe the epidemiology of Babesiosi.

US cases: majority of cases are B. microti in NE & Midwest. M-01 in Missouri. B. duncani in WA & CA European cases: B. divergens, generally more severe than US strains

What US population has experienced an increase in malaria cases?

Us military personnel/civilians/foreign residents

Besides personal protection, what are some other ways to prevent malaria?

Vaccine is underdevelopment, prophylaxis when traveling to endemic areas

Briefly describe the life cycle of Lymphatic Filariasis

W. bancrofti: Mosquito introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound. Adults produce microfilariae which are sheathed and have nocturnal periodicity (except the South Pacific microfilariae which have the absence of marked periodicity). The microfilariae migrate into lymph and blood channels moving actively through lymph and blood. A mosquito ingests the microfilariae during a blood meal. After ingestion, the microfilariae lose their sheaths and some of them work their way through the mosquito to reach the thoracic muscles, where the microfilariae develop into third-stage infective larvae. The third-stage infective larvae migrate through the hemocoel to the mosquito's prosbocis and can infect another human when the mosquito takes a blood meal.

Describe dual infections, and the two ways they can be identified

When a patient has been infected with two strains of malaria. Can either be detected from the beginning, or have a single infection detected initially, treated, and the second strain emerges weeks or months later

What are the chronic symptoms of Schistosomal Disease?

Worms mature and pair off in portal veins and migrate to target venus systems based on species (detailed in additional cards). All species may produce abdominal pain, enlarged liver, portal hypertension, and blood in stool S. haematobium linked to hematuria and risk for bladder cancer S. mansoni and japonicum occasionally embolize eggs to CNS

How is Schistosomiasis diagnosed?

Worms may be demonstrated in biopsy specimen within blood vessels Eggs in bowel or bladder tissue show granuloma formation. Large eggs are shed in stool or urine Eggs are frequently swept to the liver where pipe-stem fibrosis is seen around triad. Eosinophilia is common

What are some clinically significant Microfilarials?

Wucheria bancrofti and Brugia malayi cause lymphatic filariasis Loa loa causes African eye worm infection Onchocerca volvulus causing River blindness

Thick Film Method of Detection is sensitive for:

the detection of infection

How many cases of malaria occurred in KY in 2014?

12 cases.

What are some ways to prevent Babesiosi?

Avoid areas with tick infestation (woody areas w/ tall grass), walk in middle of path, treat clothing with Permethrin, cover up skin, wear Deet, perform body search for ticks

What are some symptoms of Severe Malaria?

Celebral malaria, Severe hemolytic anemia, Hemoglobinuria, Coagulation abnormalities, Hypotension, Acute renal failure, metabolic acidosis, Hypoglycemia, Acute respiratory distress syndrome, death

What is another name for Trypanosoma cruzi disease?

Chagas disease, can be acute or chronic

What does it mean if EIA detects both T1 and T2?

Could be either a mixed infection, or a very high parasitemia with P. falciparum. Need to correlate with thick and thin films

Briefly describe the mouse life cycle of Babesiosis.

Infected tick sends sporozoites into a mouse while taking a blood meal. The sporozoites then go into red blood cells, where they asexually reproduce by budding; differentiate into male and female gametes.

How is Malaria diagnosed?

Malaria Package: Malaria antigen, CBC to identify anemia, Reticulocyte count to classify the anemia, thick and thin blood films At UK, send out testing is discouraged, but PCR and serology TAT is available Dip stick detection used in developing countries

What malaria exists in Malaysian Borneo and Peninsular Malaysia?

P. Knowlesi

If the infected RBCs are normal or small, what strains of malaria might be present?

P. falciparum (normal RBCs) or P. malariae/knowlesi (normal or small RBCs)

What malarias are limited to tropical areas?

P. falciparum and P. malariae (summer mean temp is 21C)

What malaria is seen in sub-Saharan Africa and Vietnam?

P. ovale (tropical)

What is another name for Onchocerciasis?

River Blindness

The highest transmission rates and 98% of deaths from malaria are seen in:

Sub-Saharan Africa and Oceania

What is the Romana sign?

Swelling around eye, and lesions around mouth; at site of bite (from Trypanosoma cruzi)

How are Hookworm transmitted?

Transmitted through percutaneous invasion of larvae, larvae migrate through lung

What antigens are detected with Malarial Antigen EIA?

Two antigens are detected: T1 associated with P. falciparum infection T2 associated primarily with non-falciparum infections Note, low levels of parasitemia may be missed

The majority of Babesiosi cases are:

asymptomatic

Describe the presence of Malaria in the US.

~1,500 cases yearly (from Travelers, Immigrants, local) Local acquisition in US: mosquito bourne (63 cases 1957-2009), transfusion transmitted (96 cases 1963-2009)