Malaria

Lajina ghimire

BSC nurse/researcher

Introduction

• Malaria is a mosquito borne-disease caused by plasmodium, which is transmitted by the bite of infected female anopheles mosquito.

• The term malaria originates from Italian word: mala aria — "bad air"

• The disease is widespread in tropical and subtropical regions that are present in a broad band around the equator.[2] This includes much of Sub-Saharan Africa, Asia, and Latin America. The World Health Organization estimates that in 2012, there were 207 million cases of malaria.

History:

• Malaria or the associated disease have been noted 4000 years ago.

• References to the unique periodic fevers of malaria are found throughout recorded history, beginning in 2700 BC in China.

• Malaria may have contributed to the decline of the Roman Empire, and was so pervasive in Rome that it was known as the "Roman fever".

History:

• Scientific studies on malaria made their first significant advance in 1880, when Charles Louis Alphonse Laveran—a French army doctor working in the military hospital of Constantine in Algeria—observed parasites inside the red blood cells of infected people for the first time. For this and later discoveries, he was awarded the 1907 Nobel Prize for Physiology or Medicine.

• Scottish physician Sir Ronald Ross who proved that the mosquito was the vector for malaria for this he was awarded the Nobel prize in 1902.

History

• The first effective treatment for malaria came from the bark of cinchona tree, which contains quinine.

Malaria patient in Nepal

Epidemiology

• The WHO estimates that in 2010 there were 219 million cases of malaria resulting in 660,000 deaths.

• Others have estimated the number of cases at between 350 and 550 million for falciparummalaria and deaths in 2010 at 1.24 million up from 1.0 million deaths in 1990.

• The majority of cases (65%) occur in children under 15 years old.

• About 125 million pregnant women are at risk of infection each year; in Sub-Saharan Africa, maternal malaria is associated with up to 200,000 estimated infant deaths yearly.

Epidemiology

• P. vivax is the most common cause of malaria and is found in subtropical and temperate areas of the world.

• P. vivax and P. ovale causes relapsing malaria.

• P. falciparum is found in the tropical region and causes the most severe and fatal disease.

• P. ovale is the least common malarial species and is endemic in Africa.

Malaria prevalence in Nepal

Aetiology

• Malaria parasites belong to the genus Plasmodium (phylum Apicomplexa).

• In humans, malaria is caused by P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi.

• Among those infected, P. falciparum is the most common species identified (~75%) followed by P. vivax (~20%).

• Although P. falciparum traditionally accounts for the majority of deaths, recent evidence suggests that P. vivax malaria is associated with potentially life-threatening conditions about as often as with a diagnosis of P. falciparum infection.

• P. vivax proportionally is more common outside of Africa

Life cycle of malarial parasite

Lifecycle

• The lifecycle of malaria parasite consists of following phases:

sexual cycle: in female anopheles mosquito, definitive host.

Asexual cycle: in human, as intermediate host.• Sporozoites are the sexual form of the parasite.• When the infected female anopheles mosquito bites

the human then the sporozoites enter the human along with the saliva of the mosquito.

• Within 30 min they enter the parenchymal cells of the liver, where, during next 10-14 days, they undergo pre-erythrocytic stage of development and multipication.

Lifecycle:

• Following mitotic replication of its nucleus, the parasite is termed as schizont.

• At last the parasite rupture the liver cell and merozoites are released.

• The merozoites from the liver cell then bind to or enter the red blood cells and further develops into trophozoites.

• The multipication here results to Erythrocytic schizont.• Some merozoites of erythrocytic schizony develop into

male and female gametocytes known as microgamates and macrogamates res.

• They are sexual form and are found in peripheral blood.

Lifecycle:

• Some of the sporozoites also, on entering into the liver cells, do not undergo asexual multiplication but enter into a resting phase called hypnozoite.

• The sexual cycle of malarial parasite actually starts in the human host by the formation of gametocytes which are then transferred to mosquito for further development.

• In the midgut of the mosquito, one microgametocyte develops into 4 to 8 thread like filamentous structures named microgamates.

Lifecycle:

• From one macrogamate only one microgamate is formed.• The fertilization occurs, and the gamate is known as zygote.• The zygotes matures into an ookinete and it further

develops into an oocyst.• An oocyst mature and it increases in size and a large

number of sporozoites develop inside it.• The oocyst rupture and releases sporozoites in the body

cavity of mosquito.• The sporozoites are distributed to different organs of the

mosquito and they have a special predilection for salivary glands.

• The mosquito is now capable of transmitting the infection to man.

Symptoms of malaria:

Physical findings may include:

oElevated temperatureoPerspirationoWeakness

oEnlarged spleenoMild jaundice

oEnlargement of liveroIncreased respiration

rate.

Symptoms of malaria:

• Other symptoms of malaria are:• Dry (nonproductive) cough.• Muscle or back pain or both.• Enlarged spleen.• In rare cases, malaria can lead to impaired function of the brain or

spinal cord, seizures, or loss of consciousness.• Infection with the P. falciparum parasite is usually more serious and

may become life-threatening.• Symptoms may appear in cycles. The time between episodes of

fever and other symptoms varies with the specific parasite. Episodes of symptoms may occur:

Every 48 hours if you are infected with P. vivax or P. ovale. Every 72 hours if you are infected with P. malariae. Other common

symptoms of malaria include:

Pathogenesis:

• Incubation period: 10-14 days in P. vivax, P. falciparum and P. ovale but it is 28-30 days in P. malariae.

• The typical clinical features consists of febrile paroxysm, anaemia and spleenomegaly.

Stages of disease:

• Cold stage

• Hot stage

• Sweating stage

Cold stage:

Hot stage:

Sweating stage:

Diagnosis:

• Laboratory - thin, thick smears, antigen capture EIA, PCR etc.

• Clinical - platelets, regularly intermittent fever

• Other tests:

– CBC:

- Lukopenia, Thrombocytobenia, Esinophilia, monocytosis, Quntitative buffy coat techniqe, Urinalysis,Increase ESR

.

.Examine blood under microscope

(geimsa stain)

chest x-ray: helpful if respiratory symptoms are

present

CT scan: to evaluate evidence of cerebral edema or

hemorrhage

Medical intervention:

.

.

Polymerase chain reaction (PCR)

-determine the species of plasmodium

Dipstick test

- not as effective when parasite levels

are below 100 parasites/mL of blood

Blood examination:

Thick and thin blood film

Thick and thin smear:

Treatment:

Malaria control protocal:

Prevention:

.

Insecticides coil and

spray

Screened windows &

doors

Insecticides impregnate

d sites

Protective clothing

Fishes

Malaria project in Nepal:

• The initiation of Malaria control project was first started in Nepal in 1954 with an objective to study malaria in Terai belt of central Nepal.

• Currently malaria control activities are carried out in 65 districts at risk of malaria.