Parasitology Lecture 9 - Malaria.pdf

MALARIA

Dr. Bonifacio

Note: Italicized text were taken directly from the old trans by Gabaldon

    

PLASMODIA Class Sporozoa Only organism under this class that has no organ for motion Basis of diagnosis: Any stage of parasite in peripheral smear Malaria: “mal”-bad; “aria”-air Only caused by female Anopheles (feed on blood)

Epidemiology and Features HUMAN STRAINS I. Plasmodium falciparum a. Associated with MORTALITY b. Fatal; 67-70% II. Plasmodium vivax a. Associated with MORTALITY and MORBIDITY b. 30-35% III. Plasmodium malariae a. 0.01-1% b. BENIGN c. Found only in some isolated places in Mindanao and Palawan IV. Plasmodium ovale a. Not common in the Philippines b. Benign c. Common in African countries Examples (Ddx):  Patient from Visayas  possible strains are Vivax and Falciparum  Patient is soldier  consider the 3 strains

           

          

Geographical Distribution Tropics Subtropics Temperate 1/3 of world population (2.2 Billion) Incidence: 280 million 10 million affected each year 2-3 million die each year RP Prevalence 7.3/1000 population (1974) 67% to 70% due to P. falciparum (Patient must be hospitalized for monitoring) 30-33% due to P. vivax 0.01% due to P. malariae

Mode of Transmission Anopheles minimus flavirostris Anopheles mangyanus Bite of an infected female Anopheles mosquito (night biter) No transovarian transmission Blood transfusion (100% transmission) Accidental needle prick (IV drug users) Mother to fetus (congenital malaria)

*Female utilize blood for progeny VERTICAL TRANSMISSION  Mother to fetus HORIZONTAL TRANSMISSION  Sexual contact    

NON HUMAN STRAIN/SIMIAN STRAINS  Parasite of monkeyscan also infect human  P. knowlesi  Palawan and Mindanao  P. cynamolgi  P. simium

Malaria Data 2000 Summary Population at risk for malaria (11,337,000) Incidence per 1000 population: 0.48 Number of malaria deaths: 536 Number of patient tested for malaria: 444,668 Number of confirmed cases

*Note:   

Malaria Detection by Morphology Thick and Thin Smear  Gold Standard for Diagnosis; 50-55% (+) *low sensitivity *THIN SMEAR o Morphology o Not to be used in light infection *THICK SMEAR o If degree of parasitemia is too low o Density of Parasite Red Staining substance: CHROMATIN DOTS Bluish substance adjacent to red substance: CYTOPLASM Brown substance: HEMOZOIN

Stain used to identify Malarian Parasite:  Wright and Giemsa Stain: Routine procedure  Field’s Stain: Mass Staining Life Cycle Infective Stage  Transfer Stage Pathogenic Stage  Produce tissue alteration; signs and symptoms Diagnostic Stage  Any stage seen by naked eye; Basis for Diagnosis

Macrogametocyte Macrogamete (1:1) inside body of mosquito

Page 1 of 7 © palindrome.2012

MALARIA

Dr. Bonifacio

Note: Italicized text were taken directly from the old trans by Gabaldon

+ 1 microgamete (1:6:12) Differentiation/ Exflagellation 6-12 microgametes (only 1 is needed to fuse with macrogamete; the rest will be destroyed) Fertilization

1. young SCHIZONT 2. growing SCHIZONT 3. mature SCHIZONT Burst Release of Chromatin Dots

ZYGOTE (Product)

Infect another RBC

Ookinete

Vicious cycle

Oocyst

Differentiation of some merozoites to macro/microgametocyte

Ripe/Mature Sporozoite Inside (30,000 sporozoite)

ASEXUAL=SCHIZOGONY=Schizont=Intermediate Host=MAN SEXUAL=SPOROGONY=Sporozoite=Definitve Host=MOSQUITO

Rupture Sporozoite + Saliva of Mosquito Night (night biter) Sporozoites In the venous Circulation Liver Exo-erythrocytic phase; Pre-erythrocytic Phase; Liver Phase; Tissue Phase

30 mins-1 hour

Develop into: 1. young trophozoite 2. growing trophozoite 3. mature trophozoite Young Schizont Growing Schizont

Mature Schizont Rupture (Chromatin Dots released in circulation) Release of Merozoites ERYTHROCYTIC PHASE To become viable Infect RBC DEVELOPMENTAL STAGE 1. young trophozoite  RING FORM 2. growing trophozoite 3. mature trophozoite  single chromatin dot will split

*Young Trophozoite Source  Trophozoite  Merozoite in Eryhtrocytic Phase Infective Stage to MAN (Intermediate Host) Infective Stage to MOSQUITO (Definitive Host)

SPOROZOITE GAMETOCYTE

MAN: Schizogony  Liver Phase / Tissue Phase / Exoerythrocytic / Preerythrocytic Stage o Bite by mosquito (harboring of sporozoite) o Takes only 30 min-1 hr to start first stage o All stages develop in the liver; “hepatic schizogony” o Patient is asymptomatic  Erythrocytic Stage o Starts when mature schizont rupture and releasethe merozoites in circulation o Vicious life cycle occurs o No secondary pre-erythrocytic stage occurs (parasites will not go back to liver) o AS an alternative to schizogony, some of the parasites will undergo a sexual cycle and terminally differentiate into either micro or macrogametocyte o Gametocytes do not cause pathology in the human host and will disappear from the circulation if not taken up by mosquito MOSQUITO: Sporogenic Phase  Gametogenesis ; formation of micro and macrogametesinduced when the gametocytes are ingested by a mosquito

Page 2 of 7 © palindrome.2012

MALARIA

Dr. Bonifacio

Note: Italicized text were taken directly from the old trans by Gabaldon     

   

Macrogametes (1:1) Microgametes (1:6:12)  3 rounds of replication; only 1 microgamete is utilized to fertilize macrogamete EXFLAGELLATION: process in which thrashing flagella emerges from the microgametes Gametes fuse to become a ZYGOTE which first develops into an OOKINETE and then becomes an OOCYST where SPOROGONY takes place Oocyst undergo an ASEXUAL replication (SPOROGONY), which culminates in the production of several thousand SPOROZOITES. This generally takes 10-28 days, depending on species and temperature. Upon maturation, the oocyst ruptures and releases the sporozoites which cross the basal lamina into the hemocoel of the mosquito The sporozoites are motile and have an ability to specifically recognize the SALIVARY GLANDS. Sporozoites will then invade and transverse the salivary gland epithelial cells and come to lie within its lumen Some sporozoites will be expelled into the vertebrate host as the mosquito takes a blood meal, thus reinitiate the infection in the vertebrate host

    

   



Plasmodium vivax All stages seen in peripheral smear Only strain that causes enlarged RBC May have multiple infection Young trophozoite o RING FORM; no enlargement; 1 chromatin dot Growing trophozoite o 1/3 occupied by blue cytoplasm; irregular in shape; 1 chromatin dot; from this stage onwards, there is RBC enlargement Mature trophozoite o 2/3 bluish cytoplasm occupied; 1 chromatin dot Young Schizont o 2 chromatin dots Growing Schizont o 2-12 chromatin dots Mature schizont o 12-24 chromatin dots in cluster; the one that ruptures in vivo (circulation); releases merozoites (chromatin dots) invading other RBC Gametocytes o being developed after several weeks; INFECTIVE STGE; chromatin dots are now called CHROMATIN GRANULES o Macrogametocyte  Female  Chromatin granules on periphery  Compacted at edge o Microgametocyte  Male

Page 3 of 7 © palindrome.2012

MALARIA

Dr. Bonifacio

Note: Italicized text were taken directly from the old trans by Gabaldon 



Chromatin granules at the center  Loose arrangement The mosquito has to have both macrogametocyte and microgametocyte to be able to infect

 Has macerated area, “fimbriated” RBC IRREGULAR PAROXYSM  Caused by P. falciparum but also with mixed infection COMPARISON:

    

 

  



   

Plasmodium malariae All stages seen in peripheral smear Normal size RBC Same stages and development Growing Schizont o 2-6 chromatin dots Mature Schizont o 6-12 chromatin dots o Rosette arrangement/daisy-pattern o Peripheral arrangement o With brown substance: Hemozoint pigment product of parasite pathognomonic Young schizont: chromatin dots Presence of BAND form o Growing trophozoite stage o Seen in 15% of parasite in growing trophozoite Plasmodium falciparum Only ring form and gametocyte seen in peripheral smear Normal size RBC Ring Form o Multiple infection (more than 1 parasite in a single infected RBC) o 2 chromatin dots o PLEOMORPHIC  assume any configuration; “exclamation point”, “comma”, “swallow” or “accole pattern” Gametocyte o Mature schizont not usually seen in peripheral smear. If mature schizont is seen serious complication worst 100,000/m3 degree of infection 18-24 chromatin dots Banana-shaped/crescent-shaped  presence of chromatin granules Mixed infection: more than 1 strain of parasite

PERIOD OF SCHIZOGONY  Period of height from 1 fever to next height of fever MEROZOITE  Pathogenic stage of all plasmodian; released AFTER height/peak of fever STIPPLINGS  Cytoplasmic destruction in RBC JAMES DOT  Stippling found in P. ovale P. ovale

Incubation period Period of Schizogony (rupture of mature schizont) Type of fever

Affected red cells Effect in red cells Stipplings (cytoplasmic destruction) Stages seen in PBS

Degree of Parasitemia # of Chromatin Dots in Mature Schizont Stage Other Diagnostic features







P. falciparum 2 weeks

P. vivax

P. malariae

2 weeks

30-40 days

36-48 hrs

48 hrs

72 hrs

Malignant Tertian/ Subtertian Irregular Young and Mature Not enlarged Maurer’s / Christofer’s bodies Young trophozoite and Gametocyte 100,000/cu mm 18-24 up to 32 cluster of grapes Crescent/ banana shaped gametocyte; Knob formation at the surface of an infected RBC

Benign Tertian Regular

Quartan Regular

Young RBC only ENLARGED Schuffner’s dots

Mature RBC only Not enlarged Ziemman’s dots

All stages

All stages

50,000/cu mm 12-24 Cluster of grapes

15,000/cu mm 6-12 Rosette pattern Presence of Band Forms

Malaria Paroxysm COLD STAGE o Feeling of intense cold o Vigorous shivering o Lasts for 15-60 minutes HOT STAGE o Intense heat o Dry burning skin o Throbbing headache o Usually mid day o Lasts 2-6 hours HYPERHYDROSIS STAGE (Sweating Stage)

Page 4 of 7 © palindrome.2012

MALARIA

Dr. Bonifacio

Note: Italicized text were taken directly from the old trans by Gabaldon o o o o

o

Profuse sweating Declining temperature Exhausted and weak  sleep Lasts 2-4 hours

o o 

   

Figure. A typical pattern of temperature (fever) in



relation to blood-stage schizogony for the human malarial parasites. The fever paroxysm corresponds to the period of infected erythrocyte rupture and merozoite invasion.



*Rupture of Schizont = increased temperature = usually mid-day

Recurrence of Paroxysm RECRUDISCENCE (Recurrence) RELAPSE



P. falciparum (1 year) P. malariae (30-40 years) P. ovale P. vivax (2-3 years)

RECRUDISCENCE o P. falciparum and P. malariae o No hypnozoite o All schizonts rupture

Parasitemia falls below detectable levels and then later increases to a patent parasitemia Hide in trophozoites stimulation by parasites in trophozoites Some of the parasites that rupture another paroxysm

RELAPSE o P. ovale and P. vivax o Some of the sporozoites do not immediately undergo asexual reproduction but enter a dormant phase known as HYPNOZOITE o Hypnozoite can reactivate and undergo schizogony at a later time resulting in relapse o Reactivation of infection via hypnozoites o Mature schizont: some may remain dormant in the LIVER  via antigenic stimulation  release of chromatin dots/merozoites  rupture and release Diagnosis Thin and Thick Smear (Gold Standard) o Low sensitivity/parasitemia o Parasite density Quantitative Buffy Coat (Use of Acridine orange) affinity to DNA o Definitve diagnosis Fluorescent Ab Technique o More sensitive Immunochromatography o Malarial strips o Rapid test but NOT reliable; sensitivity only 30-65% ELISA o Used to those who are already exposed o For centralized screening and antibody screening Serologic: Antigen and Antibody Screening o Best screening for volunteer donor

**BEST TIME TO COLLECT BLOOD: BEFORE height of temperature different stages can be seen *If blood is collected AFTER height of fever: Ring forms only *If blood is collected at the height of fever: Rupture of schizontmerozoitesmistaken as platelets     

Treatment CQ + SP Artemethen – Lumefantrine (AL) Quinine (QN) in combination with either Tetracycline or Doxycycline or Clindamycin Artesunate (AS) suppository ACT (Artemisinin) usedfor all P. species; mixed infection

Page 5 of 7 © palindrome.2012

MALARIA

Dr. Bonifacio

Note: Italicized text were taken directly from the old trans by Gabaldon

     



  

    

     

 

Regimen A: Chloroquine, DOC Regimen B: Quinine (can only be administered parenterally) Liver parasite:Primaquine (AE: triggers hemolysis) o P. vivax o P. ovale Complete Drug: Regimen A + Primaquine Chemoprophylaxis NON IMMUNE o Persons travelling to an endemic area SEMI IMMUNE o Those who came in an endemic area but have been away for more than 5 years PRIMIGRAVID o Living in an endemic area for malaria; 1st time pregnancy Patients Suspected of Malaria History of Chills, Fever, Sweating History of Blood transfusion within the past 6months History of living in an endemic area for the past 2 years Patients who should be Hospitalized (+) for the asexual stage of P. falciparum; mandatory Patient showing complication/life-threatening malaria Children regardless of the strain of Plasmodia seen in the PBS Immunocompromised Pregnant women (common complication is hypoglycemia) + existing infection

  

             

Conatal or Neonatal Malaria During active labor only Parasitemia documented after 7 days but not more than 28 days of life Manifestations observed in the later course of the disease Malaria in Pregnancy Avoid primaquine since the drug may compromise the fetus Palpate liver and spleen for organomegaly Paper-white conjunctiva Yellow sclera Black urine Life-Threatening Malaria Parasites more than 100,000 cu mm or multiple infection 7gms; Hct > 20%  immediate blood transfusion Jaundice Hemorrhage  DIC Hypoglycemia with blood sugar level of 60 mg/dL or less seizure Clinical shock; kidney failure Hyperthermia (40-42 C) accompanied by seizure Prevention Health education Eradication of mosquitoes o Insecticide o Repellent o Mosquito nets

Complicated Malaria (+) for P. falciparum + drug resistance (R2 or R3) Life threatening condition G6PD in Malaria There are drugs that may trigger hemolysis in patients with G-6PD deficiency Peripheral Blood smear  20% Heinz bodies (red staining dots in the PBS) significant for the diagnosis of G-6PD G-6PD prevalent in Visayas, Panay Island, and Iloilo Primaquine  destroys parasites in the liver, however it also triggers hemolysis in G-6PD patients Congenital Malaria Parasitemia documented within 7 days of life Manifestations observed several weeks after prepatent period

Page 6 of 7 © palindrome.2012

MALARIA

Dr. Bonifacio

Note: Italicized text were taken directly from the old trans by Gabaldon

**P. malariae = NEPHROTIC SYNDROME = better prognosis than nephritic syndrome **P. falciparum = NEPHRITIC SYNDROME (immune complex nephritis)  bad prognosis

Page 7 of 7 © palindrome.2012