BY DR WAQAR MBBS, MRCP ASST PROFESSOR MALARIA BY DR WAQAR MBBS, MRCP ASST PROFESSOR

DEFINITION Malaria is an infectious disease caused by the parasite Plasmodium. This parasite is spread to the humans by the bite of female mosquito ( BAOODA) of the Anopheles species.

EPIDEMIOLOGY 1) Malaria is endemic in Africa, tropical and subtropical countries, Asia, South America. 2) Cases occur in other countries also. 3) Each year, about 500 million ppl are affected world wide. 4) The incidence & death rate has decreased since a few years, coz of protective measures & new treatments. Still, it kills many ppl. 5) In 2015, there were 438,000 deaths due to malaria, mainly in children.

MODE OF SPREAD Mosquito bite Transfusion of blood from a malaria patient i.v. drug users who have malaria & share needles 2 & 3 are very uncommon

TYPES OF PLASMODIUM Plasmodium P.Vivax P. Ovale P. malariae Falciparum The above 4 species cause malaria in humans P. Falciparum: * Causes a severe form of malaria * Can progress from simple fever to severe complications like multiorgan failure, coma and death. * More common in Africa

Types of plasmodium contd. 2) P. Vivax cause a milder form 3) P.Ovale of disease. More common 4) P. Malariae outside Africa *Vivax & Ovale can cause relapse of the infection, if not treated correctly, coz the parasites remain “dormant”(sleepy) in the liver and can re-activate later. Others don’t cause a relapse. * P. Knowlesi: A recently discovered species of plasmodium which is rare, but can cause severe malaria.

PATHOGENESIS Mosquito bites a human with malaria then bites a normal person sporozoite form of plasmodium introduced in the blood reaches the liver changes to merozoites merozoites multiply in the liver cells hepatocytes then rupture & release the merozoites merozoites infect the RBCs & cause hemolysis Whenever RBCs rupture & realease merozoites in the blood, there is a spike of fever. In falciparum, the infected RBCs attach to the blood vessel wall also & cause occlusion. This causes organ ischemia & that’s why Falciparum causes severe complications

INCUBATION PERIOD: Vivax, Ovale & Falciparum: about 2 wks Malariae : 2 to 6 wks SIGNS & SYMPTOMS: High fever wth. chills Sweating Other general S/S Anemia Splenomegaly

FEVER PATTERN In many cases of malaria, fever with chills/rigors occurs in paroxysms(episodes). In Vivax, Ovale & Falciparum: Occurs every 48 hrs. This is called “tertian” fever pattern. In P. malariae, fever occurs every 72 hrs. This is called “quartan” fever pattern. This cyclic pattern is due to rupture of RBCs & release of parasites in a “cyclic manner.”

FEVER PATTERNS

BUT BEWARE ! 1) Cyclic pattern is rare these days & many malaria patients have continuous fever or daily spikes. 2) Cyclic pattern fever does not mean “only malaria”. It can occur in many viral and bacterial fevers also.

Complications of Falciparum P. Falciparum causes severe malaria and it is a medical emergency coz patients can deteriorate rapidly. It can lead to severe complications which can be fatal. The following can be caused by Falciparum: Cerebral malaria: * Severe Falciparum malaria where CNS is also affected ( decreased consciousness, siezures, confusion, & death) 2) Blackwater Fever: * Severe Falciparum malaria where there is excessive hemolysis, causing hemoglobinuria & dark urine. This can lead to renal failure.

Complications of Falciparum Malaria 3) Blood: * Severe hemolysis * D.I.C. 4) Hypoglycemia 5) GIT: * Jaundice * Spleen rupture 6) Respiratory distress syndrome 7) Pulmonary edema

Malaria Suspicion Suspect malaria if: 1) Suggestive symptoms (cyclic fever) 2) Recent travel to endemic area ( even if many months before) 3) Past history of malaria ( may be incomplete treatment & now relapse) 4) Fever wth. splenomegaly 5) Fever wth. Anemia (? why), low platelets (?why), normal WBCs & high bilirubin

Based on severity, malaria is classified into 2 groups: Complicated & Uncomplicated Complicated malaria: Usually caused by Falciparum. It is characterised by: * Presence of any complications of Falciparum ( cerebral malaria, blackwater fever, DIC, severe hemolysis, hypoglycemia, shock) * More than 2% of the total RBCs affected 2) Uncomplicated : None of the above present

INVESTIGATIONS Blood Films: * Thick & thin films are made on the slide & examined under the microscope * 3 films should be made over 48hrs. before ruling out malaria.

MALARIA PARASITES

Malarial parasite inside RBCs

a) Thin Film:. The “type of plasmodium” is best seen on a thin film a) Thin Film: * The “type of plasmodium” is best seen on a thin film. b) Thick Film: * The “number of parasites” is best seen on a thick film. Even low levels of infections can be picked up.

Investigations (contd.) 2) Rapid Diagnostic Test (RDT): It is a quick test to diagnose malaria by detecting specific malaria antigens in a person’s blood. Not the test of first choice. 3) CBC, blood glucose, creatinine & LFTS may show abnormal values, specially in Falcip- -parum malaria

TREATMENT The choice of antimalarial drugs depends on the type of Plasmodium & whether malaria is comp- -licated or uncomplicated. Names of medicines: Chloroquine Arte-mesinin compounds (artee-mesi-nin) Mefloquin Amodiaquin (amo-dia-quin) Lumifantrine (lumi-fan-trine)

Treatment (contd) Non-Falciparum malaria: (vivax, ovale & malariae) Chloroquine tablets ( 2 day course) 2) In many areas, there is chloroquine resistance so, in that case give: Artemesinin + Mefloquin or Amodiaquin or Lumifantrine In P.Vivax & Ovale, after acute treatment is finished, give PRIMAQUINE tablets for 2 wks to eradicate the parasites in the liver. Otherwise relapse will occur later. ( No need of eradication treatment in P. malariae & Falciparum)

Treatment (contd) FALCIPARUM MALARIA ( no chloroquin given in falciparum) Uncomplicated: Give oral treatment with: a) (Artemesinin) + ( Mefloquin or Lumifantrine or Amodiaquin) 2) Complicated : Give i.v. treatment a) i.v. Artemesinin compounds or b) i.v. Quinine + oral doxycycline c) i.v. glucose for hypoglycemia d) Treatment of other complications if they occur

PREVENTION Mosquito Control: * Good hygiene in the area.( avoid stagnant water) * Mosquito sprays 2) Prevent Mosquito bites: * Apply mosquito repellant lotion on the body * Use mosquito nets * Mosquito sprays in homes 3) Medicines: Prophylactic medicines are taken if a person is is going to an area where malaria is endemic

Contd. The following medicines are used for prophy- -laxis : Mefloquin Doxycycline Atovaqone + proguanil The medicines are started 1 wk before travelling, continued throughout the stay in the endemic area & continued for 4 wks after returning.

VACCINE A vaccine for malaria prevention was introduced recently in 2015. It is called MOSQUIRIX. It is only effective against P. Falciparum and is not 100% protective.

Some Interesting Pics Artemisia Annua, the source of the antimalarial drug Artemisinins

Dr Ronald Ross received the Nobel prize for medicine in 1902 for his work on malaria

Research scientist, Tu YouYou, recvd Nobel prize in 2015 for her work on Artemesinins.

SOME QUICK POINTS Severe malaria: Plasmodium falciparum Relapse can occur : Vivax & Ovale ( Relapse Of Varda ) Drug used to prevent relapse: Primaquin Complications of Falciparum: * Cerebral malaria * Blackwater fever * Hypoglycemia * Spleen rupture * DIC

Points 5) Fever can be cyclic or continuous

WAIT ! ONE MORE LECTURE!