Epidemology and control of protozoan parasite

Epidemiology and control of protozoan parasiteSubmitted by Swarnendu Basak, Natasa Sultana, Piyali Roy, Sayantani Mandal

Epidemiology- The study and analysis of the patterns, causes, and effects of health and disease conditions in defined populations. It is the cornerstone of public health, and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiology is the branch of medicine which deals with the incidence, distribution, and possible control of diseases

All over the world most of the parasitic diseases are epidemic , such as malaria, leishmania.More than one billion people worldwide are infected by parasites causing different disease.Parasitic diseases are closely related to geographic, social and economic factors. These represent a broad group of eukaryotic and prokaryotic organisms that may cause severe diseases in animal and human populations. Parasites are the causative agents of pathologies such as Malaria. In 2008, there were 247 million cases of Malaria and nearly one million deaths from the disease, mostly among children living in Africa. In Africa, a child dies of Malaria every 45 seconds; the disease accounts for 20% of all childhood deaths

Leishmaniasis threatens approximately 350 million men, women and children in 88 countries around the world. As many as 12million people are believed to be currently infected by this disease.Schistosomiasis is a chronic, parasitic disease caused by blood flukes (trematodeworms) of the genus Schistosoma. More than 207 million people are infected with these organisms worldwide, with an estimated 700 million people at risk in 74 endemic countries.

Lymphatic filariasis affects more than 1.3 million people in 81 countries. Approximately 65% of those infected live in Southeast Asia, 30% in Africa and the remainder in other tropical areas .There is a another importance of epidemiology is molecular epidemiology is considered a powerful tool for understanding the genetic variation and evolution of pathogens. The use of the technologies based on molecular biology techniques has allowed the scientific community to reveal disease determinants and the genetic structure of parasites

In animal kingdom, about 800000 parasites have been identified and they are categorized into 33 phyla. Taxonomic classification of human parasitesEctoparasite (lice, fleas, mites)Endoparasite (schistosoma, plasmodium)Protozoan(unicellular organisms)Healminth (multicellular organisms)

Protozoan parasite-A diverse group of eukaryotes of the kingdom Protista.Primarily unicellular.Existing singly or aggregating into colonies.Usually ciliate or flagellate .Usually nonphotosynthetic. Live in water or as parasites. some major protozoan parasites are-Plasmodium , Leishmania, Giardia, Entamoeba , Trypanosoma.

Disease caused by protozoan parasiteMalaria- caused by Plasmodium parasitesspread to people through the bites of infected female Anopheles mosquitoes.Sleeping sickness-caused by infection with protozoan parasites belonging to the genus Trypanosoma.are transmitted to humans by tsetse fly (Glossina genus

Kala-Azarcaused by a protozoan parasite Leishmania transmitted to humans by the bite of infected female Phlebotomine sandflies.Amoebiasis-Also known as amebiasis or entamoebiasis.Infection caused by any of the amoebas of the Entamoeba group.

Giardiasis-Caused by the flagellate protozoan Giardia lamblia. Inhabits the digestive tract of a wide variety of domestic and wild animal species, as well as humans.

Prevalance:-Parasitic infections, caused by protozoan parasites, are among the most prevalent infections in humans in developing countries.In developed countries, protozoan parasites more commonly cause gastrointestinal infection as well as disease through blood .Intestinal parasites cause a significant morbidity and mortality in endemic countries.

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Global DistributionIn case of Malaria:99 countries are endemic to malaria in the world.Mainly found in African region followed by South-East Asia region and Eastern Mediterranean region.About 3.2 billion people are at risk of malaria.Between 2000 and 2015, malaria mortality rates fell by 60% globally and by 66% in the African region.

World Map with disease of Malaria

In case of Leishmaniasis:The disease is endemic in about 62 countries in the tropical, sub-tropical and southern Europe.More than 90% of leishmaniasis cases occur in India, Bangaladesh, Nepal, Sudan, Brazil and Ethiopia. East Africa forms the second largest focus of Leishmaniasis in the world.Largely found in underdeveloped communities.Visceral leishmaniasis(VL) killed 100,000 people out of a population of 280,000 between 1984 and 1994. 500,000 new cases of VL estimated and more than 50,000 deaths from the disease each.

Kala-azar is endemic in 54 districts in India. Mainly33 districts of Bihar. 4 districts of Jharkhand. 11 districts of West Bengal.Beside this 6 districts of eastern Uttar Pradesh.

Of Sleeping Sickness:

Sleeping sickness or African Trypanosomiasis is caused by 3 species of Trypanosoma. T. brucei gambiense - most common in central and Western Africa where humans are primary reservoir. Over 95% human infection are found in Congo, Angola,Sudan,Central Africa. T. brucei rhodesiense - most common in Southern and Eastern Asia, where game animals are thought to be primary reservoir, Tanzania, Uganda, Malawai and Zambia. T brucei brucei- it is not human infective. It causes African trypanosomiasis.

In India, few records of Trypanosome infection has been found , mostly from Maharasta.

Amoebiasis :Mainly caused by Entamoeba histolytica.Some species are non- pathogenic.Amoebiasis is most common in the Indian subcontinent, parts of Central and South America, and parts of Africa. Amoebiasis is a rare occurrence in developed countries of the world. Travelers to high risk areas where amoebiasis is endemic may acquire the infection during their travel.

The endemic areas include the tropical and sub-tropical countries of South and West Africa, Central and South America, India and Mexico.

In case of Giardiasis:G. intestinalis is found all over the world. It is one of the most common intestinal infections in the United States . Giardiasis is a enteric disease among international travelers in the United States, Canada, and Europe. G. intestinalis has high prevalence rates particularly among young children in third world countries. Giardiasis is especially common in areas with poor sanitary conditions and limited water-treatment facilities.

Giardiasis occurs globally mainly pointed area

Red coloured regions indicate maximally infected areas

Intensity of Infection:Malaria- In case of malaria parasite, About 3.2 billion people half of the worlds population are at risk . Young children, pregnant women and non-immune travellers from malaria-free areas are become infected.6.2 million malaria deaths have been averted globally since 2001. In sub-Saharan Africa 15 countries account for 80% of malaria cases and 78% deaths globally.

Since 2000, the decline in malaria incidence in 15 countries (32%) has lagged behind that of other countries globally (53%). Children under 5 are particularly susceptible to infection, illness and death. More than two thirds (70%) of all malaria deaths occur in this age group. Between 2000 and 2015, the under-5 malaria death rate fell by 65% globally.An estimated 5.9 million child lives saved between 2001 and 2015.

Leishmaniasis:The World Health Organization (WHO) reports an estimated 300,000 new cases of visceral leishmaniasis (VL) with 20,000 to 30,000 deaths annual.About 12 million people are currently infected in some 98 countries.Mostly infect the woman due to greater exposure of sand flies bites.The male to female ratio is probably about 2:1.In Southest Asia, 5-10% of VL patients in the Indian subcontinent develop post-kala azar dermal Leishmaniasis. Over 50% of VL patients in East Africa develop post-kala azar dermal leishmaniasis.

Sleeping sickness:The disease occurs in some regions of sub-Saharan Africa with the population about 70 million in 36 countries.As of 2010 it caused around 9,000 deaths per year, down from 34,000 in 1990.An estimated 30,000 people are currently infected with 7000 new infections in 2012. More than 80% of these cases are in the Democratic Republic of the Congo.Both male and female are greatly affected.The DRC currently reports more than 1000 new cases annually and accounts for 85% of the cases reported in 2014.

Amoebiasis:Approximately 50 million people have invasive disease, resulting in 100,000 deaths per year, more than 10% of the population have been reported from various developing countries.About 480 million people are infected with E. histolytica and these result in the death of between 40,000110,000 people every year.In countries where Amoebiasis is an important health problem, the majority, approximately 9007, of individuals with colonic E. histolytica infections are carriers, while the remain have invasive intestinal Amoebiasis.Amoebiasis is in 2nd position which causes the high mortality throughout the world.

About 90% of the people exposed to E. histolytica are asymptomatic or report very mild symptoms.Amoebic abscesses are 10 times more common in adult than in children.A higher frequency occurs in male than female(3:1).Giardiasis:There are 19,000 cases of Giardiasis in the United States from 2006 to 2008.In South America, rural areas of India, South-East Asia, and numerous other areas of world giardiasis may be much higher due to low income population.

Distributions is common in children less than 10 years old and adults aged of 35 to 44 years.Giardiasis is a global disease. It infects nearly 2% of adults and 6% to 8% of children in developed countries worldwide.In the United States, Giardia infection is the most common intestinal parasitic disease affecting humans.Among the child population studied revealed a gender distribution of 52.8% male and 47.2% female.Age distribution was 47.4% between 0-5 years and 52.6% between 6-15 years.

Disease caused by protozoan parasitesMajor parasitic diseases are-MalariaSleeping sicknessKala azarAmoebiasisGiardiasis

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Symptoms of malaria-Clinical symptoms of malaria:

9 to 14 days for Plasmodium (P.) falciparum

12 to 18 days for P. vivax and P. ovale

18 to 40 days for P. malariae

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FeverChillsHeadacheSweatsFatigueNauseaVomitingSevere anemiaKidney failure (high mortality)

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The cyclic pattern of malaria symptoms is due to the life cycle of malaria parasites .they develop, reproduce, and are released from the red blood cells and liver cells in the human body .

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Physical and morphological alteration caused by malarian parasite-Plasmodium falciparum leads to structural, biochemical, and mechanical modifications to the host red blood cells

formation of parasitophorus vacuoles

loss of cell volume, and the appearance of small nanoscale protrusions or knobs on the membrane surface.

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considerable amount of hemoglobin (Hb) is digested by parasites during intraerythrocytic development and converted into insoluble polymerized forms of heme, known as hemozoin.

loss of RBC deformability cause anaemia .

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Symptoms of sleeping sickness:-

In the first stage, the trypanosomes multiply in subcutaneous tissues, blood and lymph. This is known as a hemolymphatic phase, which entails bouts of fever, headaches, joint pains and itching.

In the second stage, the parasites cross the blood-brain barrier to infect the central nervous system. This is known as the neurological phase.

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Clinical symptoms:- Fever Personality changes Disturbance of sleep patterns Troubles with walking and talking Aching muscles and joints Slurred speech Seizures Swelling around the eyes and hands Headaches Fatigue Prolonged sleep Death shortly happens a few months, after the invasions of the central nervous system.

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Physical and morphological alternation

The primary clinical signs are an intermittent fever, signs of anemia, lymphadenopathy and weight loss.Neurological signs, dependent edema, cardiac lesions, diarrhea, keratitis, lacrimation, appetite loss and other clinical signs have also been reported .Affected animals have enlarged lymph nodes and signs of severe anemia, and they develop widespread visceral and mucosal hemorrhages, particularly in the gastrointestinal tract .In one outbreak, the main hemorrhagic sign was bleeding from the ears. Weight loss can be severe. This syndrome can be rapidly fatal.

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Clinical symptoms of kala-azar:-

Fever Fatigue Weakness Pallor of skin and mucous membranes Loss of appetite In case of visceral leishmaniasis hepatosplenomegally occur Weight loss

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Physical and morphological alteration:-

parasitic invasion of the blood and reticulo-endothelial system (that is, the general phagocytic system), such as enlarged lymph nodes, spleen and liver.

Fatigue and weakness are worsened by anaemia, which is caused by the persistent inflammatory state, hypersplenism (the peripheral destruction of erythrocytes inthe enlarged spleen) and sometimes by bleeding.

Patient with V.L should be assessed for possible cutaneous Leishmaniasis called post- kala-azar dermal Leishmaniasis . Splenomegally (with the spleen most often soft and non tender) typically is more impressive than hepatomegally and the spleen can in fact be massive

Mucosal involvement generally is manifested first by pesistent unusual nasal symptom (e.g. epistaxis), with erythema and edema of the nasal mucosae, and then by progressive ulcerative,nasopharyngeal destruction.

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In case of Amoebiasis-

Clinical symptoms of amoebiasis:Most people with this infection do not have symptoms. If symptoms occur, they are seen 7 to 28 days after being exposed to the parasite.Mild symptoms are-Abdominal cramps Diarrhea, Passage of 3 to 8 semiformed stools per day, or passage of soft stools with mucus and occasional blood Fatigue Excessive gas Rectal pain while having a bowel movement (tenesmus) Unintentional weight loss.Severe symptoms:-Abdominal tenderness Bloody stools, including passage of liquid stools with streaks of blood, passage of 10 to 20 stools per day Fever Vomiting

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: Physical and morphological alteration

The E. histolytica parasite can cause inflammation in the lining of host gut (intestines). This condition is known as amoebic colitis .

The disease is often mild and can just lead to tummy (abdominal) pain and diarrhoea.

severe inflammation with ulceration of the intestinal lining can occur in some people and so-called 'amoebic dysentery' can develop.

symptoms of amoebic dysentery include severe abdominal pain and diarrhoea which can contain blood and mucus.

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High temperature (fever) may be another symptom but this is not common loss of appetite and weight los Some people with amoebic colitis may just develop bleeding from their back passage (rectal bleeding) with no diarrhoea.

few people with amoebic colitis, an 'amoeboma' can develop.

Anaemia is another complication of amoebic colitis due to blood loss in the bloody diarrhea. The most typical presentation of amebic liver abscess is fever right upper quadrant pain, and tenderness.

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In case of Giardiasis

Physical and morphological alteration :-Some people with giardia infection never develop signs or symptoms but still carry the parasite and can spread it to others through their stool.signs and symptoms usually appear one to three weeks after exposure and may include.

Watery, sometimes foul-smelling diarrhea that may alternate with soft, greasy stools Fatigue or malaise Abdominal cramps and bloating

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Clinical symptoms:- Vomiting Urticaria Flatulence Malaise, weaknes Various neurologic symptoms (e.g.., irritability, sleep disorder, mental depression, neurasthenia) Anorexia Gas or flatulence Nausea Weight loss

Physical and morphological alternation

less common symptoms include itchy skin, hives, and swelling of the eye and joints .

Sometimes, the symptoms of giardiasis might seem to resolve, only to come back again after several days or weeks.

Giardiasis can cause weight loss and failure to absorb fat, lactose, vitamin A and vitamin B12 .

When the parasite does cause symptoms, the illness usually begins with severe bouts of watery diarrhea, without blood or mucus .

giardiasis affects the body's ability to absorb fats from the diet .

diarrhea seen in giardiasis contains unabsorbed fats - so it floats and is very foul-smelling and shiny .

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Control And Prevention

for MALARIA

Treatment and prophylaxis Quinine, quinidineChloroquine, amodiaquine, and relativesPyrimethamine and combinationsProquanil and chlorproguanilMefloquineHalofantrineArtemisinin and derivatives (qinghaosu)Antibioticstetracycline, clindamycin, rifampicin

CausalprophylaxisPrimaquine

Combination chemotherapy, e.g., artemisininplus XNow essential despite increase in adverse reactions and cost

VACCINES

Directed against Sporozoites (plus)

Asexual forms (Patarroyo)

Gametocytes (plus) transmission-blocking

Rational use of vector control methodsAn effective vector control method should be able to reduce the vectorial capacity of mosquitoes. There are five determinants of the choice of vector control method applied in an area. These are:Intensity of the disease transmission or the magnitude of the malaria burden;Vector behaviour, human behaviour and environment;Availability of resources;Feasibility of timely and correct application;Possibility of sustainabilityMalaria Free Zone:In this zone continuous surveillance should be maintained to keep watch of introduction of malaria in such zones.Seasonal Transmission Zone:The most cost effective control method includes the use of Indoor Residual Spray (IRS). This includes epidemic prone areas. However, the coverage of IRS should be about 80% for high impact.Endemic And Holoendemic Zone:In such areas the most cost effective method of control is the use of Insecticide Treated Nets (ITNs). The coverage must be in more than 80% of the community members for it to have impact.VECTOR CONTROL

General Measures for Prevention and Control

Controlling mosquito breeding;

Preventing mosquitoes from biting people;

Killing adult mosquitoes before they bite people;

for SLEEPING SICKNESS

A-B-C Method: Awareness of Risk Bite Avoidance

Chemoprophylaxis

And also,

avoiding the bushy areas and using the bed nets at the bed time

DrugsSpecies Phase Dosage Route Common side effects Pentamidine isethionate T. gambiense acute 7-10 doses of 4mg/kg per day IM DiarrheaDizzinessHeadacheUpset stomachNauseaSuramin sodium T. gambiense

T. rhodisiense acute5mg/kg on the 1st day, 10 on the 3rd and 20 on the 5th,11th, 23rd and 30th IVRenal failureAnaphylactic shocksSigns of neurotoxicitySevere cutaneous reactions Melasoprol T. gambienseT. rhodisiense chronic3-4 series of 3-4 injections per day IVReactive encephalopathic syndrome Elfornithine T. gambiense chronic400mg/kg per day in 4 daily infusions for 1-2 wks. IVDiarrheaPancytopeniaConvulsionHallucinationNifurtimox T. gambienseT. cruzi chronic400mg/kg per day in 4 daily infusions for 1-2 wks. OralAnorexiaNeurological problems

TREATMENT

TREATMENT

Good nursing

Diet

Antibiotics

Pentavalent antimony (sodium stibogluconate and meglumine antimoniate have been used as first-line chemotherapeutic agents)PentamidineAmphotericin B, which is a macrolide, is another drug of second choice used in the treatment of leishmaniasis

for KALA AZAR

CONTROL

Vector controlReservoir controlTreatment of active casesVaccination

for AMOEBIASIS

TREATMENT

For invasive forms: metronidazole

For luminal forms: Iodoquinofonum, paromomycin, diloxanide

Individual measuresDiagnosis and treatment of E. histolytica patientsSafe drinking water (boiling or 0.22 m filtration)Cleaning of uncooked fruits and vegetablesPrevention of contamination of foods

Chemotherapeutic Trial

Community measuresPublic services and utilitiesAdequate disposal of human stoolsSafe and adequate water supplyPrimary health care systemsHealth education (washing hands, cleaning and protecting food, controlling insects)Specific surveillance programs and Control programs integrated into ongoing sanitation & diarrhea controlHealth RegulationsControl of food vendors and food handlersControl of flies and cockroaches

forGIARDIASISWhen signs and symptoms are severe or the infection persists, doctors usually treat giardiasis with medications such as: Metronidazole (Flagyl): Metronidazole is the most commonly used antibiotic for giardia infection. Side effects may include nausea and a metallic taste in the mouth. Don't drink alcohol while taking this medication. Tinidazole (Tindamax): Tinidazole works as well as metronidazole and has many of the same side effects, but it can be given in a single dose. Nitazoxanide (Alinia): Because it comes in a liquid form, nitazoxanide may be easier for children to swallow. Side effects may include nausea, flatulence, yellow eyes and brightly colored yellow urine.

Children and adults who have giardia infection without symptoms usually don't need treatment unless they're likely to spread the parasites. Many people who do have problems often get better on their own in a few weeks

There are no consistently recommended medications for giardiasis in pregnancy because of the potential for adverse drug effects to the baby. If your symptoms are mild, your doctor may recommend delaying treatment until after the first trimester. If treatment is necessary, discuss the best available treatment option with your doctor

Prevention by maintenance of good hygeine

Wash hands with soap and clean running water for at least 20 seconds; rub hands together to make a lather and be sure to scrub the backs of your hands, between fingers and under the nails :Before and after taking foodBefore and after using toiletAfter coughing, sneezing or blowing noseThoroughly washing your hands after gardening can help prevent exposure to parasitic diseases .

To reduce the risk of spreading the disease, children with diarrhea should be removed from child care settings until the diarrhea has stopped. Protect others by not swimming if you have diarrhea (this is most important for children in diapers). If diagnosed with giardiasis, do not swim for at least 1 week after diarrhea stops. Shower before entering the water. Wash children thoroughly (especially their bottoms) with soap and water after they use the bthroom or after their diapers are changed and before they enter the water. Minimize contact with animal feces in order to prevent spread of infections

Thank you

LocationClinical ClassDrug NameDrug Action

Intestinal

AsymptomaticIodoquinofonnum lumenal amebicide

Mild to moderate intestinal diseaseMetronidazole

tissue amebicide

Severe intestinal disease Metronidazole plus a lumenal drugboth

Extraintestinal

Hepatic diseaseMetronidazole plus a lumenal drugboth