MOSQUITO-BORNE MOSQUITO-BORNE DISEASESDISEASES

Brief history & pathophysiology by Iqra Zulfiqar (R#33)

What is Malaria?What is Malaria?

• Vector-borne infectious disease caused by single-celled protozoan parasites of the genus Plasmodium.

• Transmit by bite from an infective female Anopheles mosquito.

• Widespread in tropical and subtropical regions.

• Probably one of the oldest diseases known to mankind that has had profound impact on our history.

Alternative names: oQuartan malariaoFalciparum malariaoBlackwater feveroTertian malaria

At risk for malaria: 40% of the world’s population40% of the world’s population

Female Anopheles are:Anthropophilic : from humans Zoophilic : from animals Endophagic : prefer to bite indoors Exophagic : prefer outdoor biting

What causes Malaria?What causes Malaria?

• Malaria is caused by an infection by one of four single celled Plasmodia species, they are: falciparum, vivax, malariae, and ovale.

The most dangerous of the four is P.falciparum• In the human body, the parasites multiply in the liver, and

then infect red blood cells. • Transmission of Malaria do not occur <160C and >330C.• Malaria is fourth leading cause of death• In Pakistan majorly infectious species of plasmodium are:

P. vivax 70% P. falciparum 30%

Species Infecting HumansSpecies Infecting Humans

Five Species known to infect ManPlasmodium vivax – Benign Tertian, Tertian Malaria(Grassi and Feletti)P.ovale - Ovale tertian Malaria(Stephens)P.malariae – Quartan malaria (Laveran)P.falciparum – Falciparum malaria or Malignant Tertian malaria(Welch)P. knowlesi (Sinton and Muller)

Species Infecting HumansSpecies Infecting Humans

Plasmodium falciparumMalignant tertian (Cerebral)

Plasmodium vivaxTertian

Plasmodium ovaleTertian

Plasmodium malariaeQuartan Rare & Mild

Common & Severe

AN ANCIENT DISEASE – AN ANCIENT DISEASE – The History Of MalariaThe History Of Malaria

Malaria parasites have been with us since the dawn of time. They probably originated in Africa (along with mankind), and fossils of mosquitoes up to 30 million years old, show that the malaria vector, the malaria mosquito, was present well before the earliest history.

Events on MalariaEvents on Malaria

1880 1898 1948 1955 1970 1976

Charles Louis Alphose Lavern

discovered malarial parasite

in wet mount

Roland Ross - Life cycle of parasite

transmission, wins Nobel Prize

in 1902

WHO starts world wide malaria eradication

programme using DDT

Trager and Jensen did in vitro

cultivation of parasite

Site of Exoerythrocytic development in Liver by Shortt and Garnham

Mosquitos develop

resistance to DDT Programme fails

Nobel Prizes in MalariaNobel Prizes in Malaria

Exo-erythrocytic (hepatic) cycle

Hypnozoites

Sporozoites

Salivary Gland

Gametocytes

Erythrocytic Cycle

Zygote

Oocyst

Stomach Wall

Pre-erythrocytic (hepatic) cycle

Pathophysiology- Life Cycle of Pathophysiology- Life Cycle of MalariaMalaria

Animated Il lustration Of Animated Il lustration Of PathophysiologyPathophysiology

Period of Pre erythrocytic cyclePeriod of Pre erythrocytic cycle• P.vivax 8 days• P.falciparum – 6 days• P.malariae - 13 – 16 days,• P.ovale 9 days Affinity of Parasite to ErythrocytesAffinity of Parasite to Erythrocytes• P.vivax Young red blood cells• P.malariae Old red blood cells• P.ovale Young red blood cells• P.falciparum Infects all age groups

o Pregnant women have increased susceptibility to P. falciparum malaria; in malaria-endemic countries, P. falciparum contributes to 8-14% of low birth weight, which in turn decreases the chance of a baby’s survival.

o Malarial parasite found mostly in warmer climates, malaria breeds where there is an abundance of humidity and rain.

o Biologic characteristics and behavioral traits can influence an individual's risk of developing malaria and, on a larger scale, the intensity of transmission in a population.

o An experienced laboratory technician or pathologist can distinguish between P. falciparum, P. vivax, P. malariae and P. ovale based on the appearance of the parasites and infected blood cells. Under the microscope, P. knowlesi can resemble either P. falciparum or P. malariae. Increasingly reference diagnostic tools like PCR are employed to confirm malaria infection and to determine definitively which species are involved.

o Patient’s Performa: Name – Mr. X Age – 26 yrs Gender – Male Date of admission – 06/10/12 Date of discharge – 10/10/12Chief complaintsChills, intermittent fever, vomiting, back pain, fatigue, head ache

X 3days.History of present illnessBack pain ,headachePersonal HistoryNon-alcoholic, Non-smoker

How we relate these sign & symptoms with Malaria and How we relate these sign & symptoms with Malaria and what sort of lab diagnosis we can do, to confirm the what sort of lab diagnosis we can do, to confirm the diagnosis of patient?diagnosis of patient?

Some important factors regarding Some important factors regarding symptoms…symptoms…

The time from the initial malaria infection until symptoms The time from the initial malaria infection until symptoms appearappear

Symptoms..Symptoms..COMMON SYMPTOMSCOMMON SYMPTOMS

Appearance of Common Symtoms..

The common first symptoms – fever, headache, chills and vomiting – usually appear 10 to 15 days after a person is infected. If not treated promptly with

effective medicines, malaria can cause severe illness and is often fatal.Clinical eventsClinical events

The symptoms often associated with malaria are due to bursting red blood cells and clogged capillaries of major organs. Infection occurs when an infected

anopheles mosquito feeds on an individual releasing sporozites into the blood stream. Mosquitos can carry more than one species and thus can infect peoples

with more than one species.Periodicity CluesPeriodicity Clues

Periodicity can be clue in Diagnosis and species relation:¤Malaria tertiana: 48h between fevers (P. vivax and ovale)

¤Malaria quartana: 72h between fevers (P. malariae) ¤Malaria tropica: Irregular high fever (P. falciparum)

Symptoms..Symptoms..CLASSICAL SYMPTOMSCLASSICAL SYMPTOMS

Symptoms..Symptoms..CLASSICAL SYMPTOMSCLASSICAL SYMPTOMS

Symptoms..Symptoms..CLASSICAL SYMPTOMSCLASSICAL SYMPTOMS

Broad Clinical Manifestations• Fever & Sweating • Anemia • Splenomagaly (enlarged spleen)• Irratability • Coma• Retinal Hemorrages • Algid Malaria ( a shock-like syndrome) • Respiratory distress syndrome

ComplicationsComplications• Cerebral Malaria• Pulmonary edema (fluid buildup in the lungs) or acute respiratory distress

syndrome (ARDS)• Cardiovascular collapse and shock• Black water Fever• Acute kidney failure • Metabolic acidosis (excessive acidity in the blood and tissue fluids), often in

association with hypoglycemia

DIAGNOSIS OF MALARIADIAGNOSIS OF MALARIA

Based on the patient's symptoms and on physical findings at examination.

Clinical DiagnosisClinical Diagnosis

Microscopic DiagnosisMicroscopic Diagnosis

1. Blood Smear

• Malaria parasite identified by examining under the microscope a drop of the patient's blood, spread out blood smear on a microscope slide Blood smear stained with Giemsa’s stainMicroscopic demonstration still the Gold standard in Diagnosis Blood Smear Stained

With Giensa Stain

Collection of Blood SmearsCollection of Blood Smears

5.Touch the drop of blood to the slide from below.

4.Slide must always be grasped by its edges.

2.Puncture at the side of the ball of the finger.

3.Gently squeeze toward the puncture site.

1.The second or third finger is usually selected and cleaned.

Preparing thick and thin f i lmsPreparing thick and thin f i lms

1.Touch one drop of blood to a clean slide.

2.Spread the first drop to make a 1 cm circle.

3.Touch a fresh drop of blood to the edge of another slide.

6.Wait for both to dry before fixing and staining.

5.Pull the drop of blood across the first slide in one motion.

4.Carry the drop of blood to the first slide and hold at 45 degree angle.

2. Fluorescent Microscopy

• Modification of light microscopy • Fluorescent dyes detect RNA and DNA that is contained in parasites• Requires Fluorescent microscope • Nuclei of malaria parasites fluoresce bright green and cytoplasm red. • Staining itself is cheap• Sensitivities around 90%

3. Quantitative Buffy Coat

• Rapid and precise method in Diagnosis

• Useful for screening large numbers of sample

• Requires centrifuge, special stains

• Immunochromatographic test (RDTs) • Various test kits are available to detect

antigens derived from malaria parasites.• Provide results in 2-15 minutes.• These Rapid Diagnostic Tests (RDTs) offer a

useful alternative to microscopy in situations where reliable microscopic diagnosis is not available.

• RDTs Test Formats;• Plastic Cassette• Card• Dipstick• Hybrid Cassette Dipstick

Antigen DetectionAntigen Detection

RDTs: Test Format

Molecular DiagnosisMolecular Diagnosis

• Polymerase chain reaction (PCR)• Molecular technique to identify

parasite genetic material

Lane S: Molecular base pair standard (50-bp ladder).  Black arrows :size of standard bands. Lane 1: P. vivax (size: 120 bp). Lane 2: P. malariae (size: 144 bp). Lane 3: P. falciparum (size: 205 bp). Lane 4: P. ovale (size: 800 bp).

SerologySerology• Serology detects antibodies against

malaria parasites• Using either indirect

immunofluorescence (IFA) or enzyme-linked immunosorbent assay (ELISA).

¤Normocytic anemia of variable severity.¤Liver function tests may be abnormal¤Presence of protein and casts in the Urine of children with P.malariae is suggestive of Quartan nephrosis.¤In severe Falciparum malaria with renal damage may cause oliguria and appearance of casts, protein, and red cells in the Urine

Other Laboratory Findings….Other Laboratory Findings….

PREVENTIONPREVENTION

ANTIMALARIAL DRUGSANTIMALARIAL DRUGS

• Antimalarial drugs are used for the treatment and prevention of malaria infection.

• Most antimalarial drugs target the erythrocytic stage of malaria infection, which is the phase of infection that causes symptomatic illness.

• Treatment of the acute blood stage infection is necessary for malaria caused by all malaria species.

• For infection due to Plasmodium ovale or P. vivax, terminal prophylaxis is required with a drug active against hypnozoites (which can remain dormant in the liver for months -- and occasionally years -- after the initial infection.

Drug ClassificationDrug Classification

QuinolonesQuinolones

TetracyclineDoxycycline

and clindamycin

ArtesunateArtemether

Artelinic acidArtemotil

Anti folatesAnti folates Anti Anti MicrobialMicrobial

ArtemisininsArtemisinins

Chloroquine Amodiaquine

Quinine Quinidine

Mefloquine Primaquine

Sulfonamides, Pyrimethamine,

Proguanil and

Dapsone

• Include chloroquine, amodiaquine, quinine, quinidine, mefloquine, primaquine, lumefantrine and halofantrine. • These drugs have activity against the

erythrocytic stage of infection; primaquine also kills intrahepatic forms and gametocytes. • The drugs act by accumulating in the parasite

food vacuole and forming a complex with heme that prevents crystallization in the plasmodium food vacuole. • Heme polymerase activity is inhibited, resulting

in accumulation of cytotoxic free heme.

QUINOLINE DERIVATIVESQUINOLINE DERIVATIVES

4-aminoquinolines

• ChloroquineChloroquine: : has activity against the blood stages of Plasmodium ovale, P. malariae, and susceptible strains of P. vivax and P. falciparum.

• Mechanism Of Action : Mechanism Of Action : Binds to and inhibits DNA and RNA polymerase; interferes with metabolism and hemoglobin utilization.

• Chloroquine concentrates within parasite acid vesicles and raises internal pH resulting in inhibition of parasite growth.

DOSING: ADULTSDOSING: ADULTS• Malaria, suppression or prophylaxis: Oral: 500 mg/week on the same day each

week; begin 1-2 weeks prior to exposure; continue for 4-6 weeks after leaving endemic area; if suppressive therapy is not begun prior to exposure, double the initial loading dose to 1 g and administer in 2 divided doses 6 hours apart, followed by the usual dosage regimen.

• Malaria, acute attack: Oral: 1 g on day 1, followed by 500 mg 6 hours later, followed by 500 mg on days 2 and 3.

• Side EffectsSide Effects• Chloroquine is only administered orally; intravenous infusion is associated with

significant toxicity.• Side effects of chloroquine include headaches, dizziness, abdominal discomfort,

vomiting, and diarrhea.

4-methanolquinolines

• Quinine & Quinidine: Quinine & Quinidine: Quinine is a derivative from the bark of the South American Cinchona tree and exists in oral and parenteral forms and is the most commonly used parenteral antimalarial drug.

• Quinidine is a stereoisomer of quinine available in parenteral formulation and is very effective for treatment of severe malaria.

• Mechanism of Action: Mechanism of Action: Depresses oxygen uptake and carbohydrate metabolism; intercalates into DNA, disrupting the parasite's replication and transcription

• Dosing-Adult :Dosing-Adult :Treatment of chloroquine-

resistant malaria:

648 mg every 8 hours for 7 days with tetracycline,

doxycycline, or clindamycin.

• Dosing-Adult :Dosing-Adult :Dosage expressed in terms of

the salt: 267 mg of quinidine gluconate = 275

mg of quinidine polygalacturonate = 200 mg

of quinidine sulfate.

USE:USE:Quinidine gluconate (I.V.

formulation) and quinidine sulfate: Treatment of malaria (Plasmodium

falciparum).

• Adverse effects Adverse effects of quinine and quinidine include a complex of symptoms referred to as cinchonism, includes:

• Mefloquine: Mefloquine: is an orally administered medication used in the prevention and treatment of malaria.

• Mechanism Of Action : Mechanism Of Action : The exact mechanism of action is uncertain. However, it is proposed to share a similar mechanism of action with chloroquine, which is inhibition of heme polymerase.

• Use:Use:Treatment of acute malarial infections and prevention of malaria.

Dosing: Dosing: • ADULTS: ADULTS: Malaria treatment (mild-to-moderate infection): Oral: 5 tablets as a

single dose. If clinical improvement is not seen within 48-72 hours, an alternative therapy should be used for retreatment.

• Malaria prophylaxis: Oral: 1 tablet (250 mg) weekly starting 1 week before arrival in endemic area, continuing weekly during travel and for 4 weeks after leaving endemic area

• PEDIATRIC: PEDIATRIC: Malaria treatment: Oral: 20-25 mg/kg in 2 divided doses, taken 6-8 hours apart (maximum: 1250 mg).

• If clinical improvement is not seen within 48-72 hours, an alternative therapy should be used for retreatment.

• Malaria prophylaxis: Oral: 5 mg/kg/once weekly (maximum dose: 250 mg) starting 1 week before arrival in endemic area, continuing weekly during travel and for 4 weeks after leaving endemic area.

• Adverse effects Adverse effects includes:

8-aminoquinolines

• Primaquine: Primaquine: is the only 8-aminoquinoline in clinical use. • Largely used to prevent relapse of P. ovale and P. vivax

malaria by eliminating dormant hypnozoites, and it also has activity against the pre-erythrocytic stage and gametocytes of P. falciparum.

• Mechanism Of Action : Mechanism Of Action : Eliminates the primary tissue exoerythrocytic forms of P. falciparum; disrupts mitochondria and binds to DNA.

Dosing: Dosing:   ADULTS

The CDC recommends screening for G6PD deficiency prior to initiating treatment with primaquine. (15 mg)

• It can cause hemolytic anemia in those with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Therefore, patients should receive primaquine only if G6PD deficiency has been excluded.

• Adverse effects Adverse effects includes:

Drug ClassificationDrug Classification

QuinolonesQuinolones

TetracyclineDoxycycline

and clindamycin

ArtesunateArtemether

Artelinic acidArtemotil

Anti folatesAnti folates Anti Anti MicrobialMicrobial

ArtemisininsArtemisinins

Chloroquine Amodiaquine

Quinine Quinidine

Mefloquine Primaquine

Sulfonamides, Pyrimethamine,

Proguanil and

Dapsone

• Antifolates include sulfonamides, pyrimethamine, proguanil and dapsone. • These drugs act synergistically to target

enzymes involved in folate synthesis, a pathway required for parasite DNA synthesis.

ANTI-FOLATESANTI-FOLATES

Sulfadoxine and pyrimethamineSulfadoxine and pyrimethamine

•Mechanism Of Action : Mechanism Of Action : Sulfadoxine interferes with bacterial folic acid synthesis and growth via competitive inhibition of para-aminiobenzoic acid; pyrimethamine inhibits microbial dihydrofolate reductase, resulting in inhibition of tetrahydrofolic acid synthesis

•Use: Use: Treatment of Plasmodium falciparum malaria in patients in whom chloroquine resistance is suspected.

• Dose:Dose:• Adults - Adults - Treatment of acute malaria attacks: Oral: A single dose of

the following number of Fansidar® tablets is used in sequence with quinine or alone: 3 tablets

• Malaria prophylaxis: Malaria prophylaxis: A single dose should be carried for self-treatment in the event of febrile illness when medical attention is not immediately available: Oral: 3 tablets

• Adverse Effects:Adverse Effects:• Mild adverse effects include gastrointestinal upset and headache.

Mild bone marrow suppression may occur, and sulfadoxine can precipitate hemolysis in patients with G6PD deficiency.

Drug ClassificationDrug Classification

QuinolonesQuinolones

TetracyclineDoxycycline

and clindamycin

ArtesunateArtemether

Artelinic acidArtemotil

Anti folatesAnti folates Anti Anti MicrobialMicrobial

ArtemisininsArtemisinins

Chloroquine Amodiaquine

Quinine Quinidine

Mefloquine Primaquine

Sulfonamides, Pyrimethamine,

Proguanil and

Dapsone

• Tetracycline, doxycycline, and clindamycin target prokaryotic protein synthesis. • In malaria parasites, these drugs appear to

target the apicoplast, an organelle derived from prokaryotic ancestors. • They have relatively slow antimalarial activity

because they exert their toxic effects in the subsequent cycle of cell division. • They are typically paired with fast-acting

antimalarials (usually quinine). • Doxycycline has a longer half life than

tetracycline so is used more commonly.

ANTI-MICROBIALSANTI-MICROBIALS

• Adverse effects Adverse effects are common with the tetracyclines • Gastrointestinal discomfort and candidiasis are

the most frequent complaints. • Doxycycline therapy also poses a risk of

esophageal ulceration.

Drug ClassificationDrug Classification

QuinolonesQuinolones

TetracyclineDoxycycline

and clindamycin

ArtesunateArtemether

Artelinic acidArtemotil

Anti folatesAnti folates Anti Anti MicrobialMicrobial

ArtemisininsArtemisinins

Chloroquine Amodiaquine

Quinine Quinidine

Mefloquine Primaquine

Sulfonamides, Pyrimethamine,

Proguanil and

Dapsone

• The artemisinins are derived from the leaves of the Chinese sweet wormwood plant, Artemisia annua. • They have been used in China for the treatment

of malaria for over 2000 years and came to attention outside of China in the 1970s and 1980s.

ARTEMISININ ARTEMISININ DERIVATIVESDERIVATIVES

• Mechanism of Action: Mechanism of Action: Artemisinins act by binding iron, breaking down peroxide bridges leading to the generation of free radicals that damage parasite proteins.

• They act rapidly, killing blood stages of all Plasmodium species and reducing the parasite biomass.

• Artemisinins have the fastest parasite clearance times of any antimalarial.

• Artemisinins are active against gametocytes, the parasite form that is infectious to mosquitoes.

• Intravenous artesunate is used for the treatment of severe malaria.

• Dosing: Dosing: If used alone (via the parenteral, rectal or oral route), artesunate must be administered for 5-7 days.

• Artemisinins are generally well tolerated.

• Type 1 hypersensitivity to the artemisinin compounds has been reported.

• Adverse Effects Adverse Effects of orally-administered artemisinins demonstrated transient neurological abnormalities( nystagmus and disturbances in balance)

Brief history & pathophysiology by Sana Chauhdry (R#08)

What is Dengue Fever?What is Dengue Fever?

a debilitating viral disease of the tropics, transmitted by mosquitoes, and causing sudden fever and acute pains in the joints.

ALTERNATIVE NAMES Hemorrhagic dengue Dengue shock syndrome Philippine hemorrhagic Thai hemorrhagic fever Singapore hemorrhagic fever

OriginOriginThe origin is still debatable.

Scientist proposed it originated from Asian

Forests.

Early outbreaks recorded:• 992 in Chinese Encyclopedia• 1635 in French West Indies• 1699 in Panama.

17711771

• Dr. Jose Sabater

• Disease called “Break-Bone Fever”

• Treated using small quantities of Rum.

17801780

• Dr. Benjamin Rush

• Disease called “Bilious Remitting Fever”

18011801• People started calling it “Dengue”

• Dengue is Spanish word for “Fastidious”

• Some believe that name came from Swahili Phrase “Ka Dinga Pepo”

(Disease caused by an evil spirit)

19531953• First Epidemic of Severe

Dengue.

• Disease spread in South East Asia during the next 20 years.

Causative agent of dengue

Main vector

Aedes Aegypti mosquito

Having white band and scale patterns on its legs

and thorax.

Having white band and scale patterns on its legs

and thorax.

The mosquito is attracted by the body odors, carbon dioxide and heat emitted from the animal or humans.Aedes are day-biters, most active during dawn and dusk.

DO YOU KNOW????DO YOU KNOW????

Mode of transmission

Symptoms….Symptoms….

• Travel history and symptom profile• Detection of antibodies against the

virus• Complete blood count• Liver function test etc.

Diagnosis of dengue

Do’s for dengue patient

Do’ for dengue patient

Don’t for dengue patient

Prevention of dengue fever

This is what you can do to help….This is what you can do to help….

• No vaccine or drugs are available for the prevention of dengue

• Preventive measure should be taken to avoid the bite of the mosquito– Well screen accommodations or air conditioning– Use of insecticide indoors– Apply insect repellent to skin and clothing. The most effective

are the ones with DEET– Empty , clean or cover any standing water that can be a

mosquito-breeding site

Preventive measure for traveler

• The times of higher risk of being bitten by the female mosquito is 2 to 3 hours after daybreak and 3 to 4 hours before nightfall

• The mosquito can feed indoors as well as outdoors

Final word of advice for travellers

Home remedies for dengue

REFERENCESREFERENCES Katzung & Trevor's Pharmacology Examination and Board

Review Lippincott's Illustrated Reviews: Pharmacology

Comprehensive Pharmacy Review by Leon Shargel http://www.nytimes.com/health/guides/disease/malaria/overview.html http://www.cdc.gov/malaria/ http://www.who.int http://www.who.int/tdr/publications/documents/dengue-life-cycle.swf http://realityviews.blogspot.com/2010/08/dengue-fever-know-25-dengue-natural.html http://www.slideshare.net/brittgow/malaria-powerpoint http://www.slideshare.net/PietriGirl/dengue-1334860 http://www.malariajournal.com/content