Introduction To Coccidia & Malaria PDF

INTRODUCTION TO COCCIDIA & MALARIA 1 Dr. NANTHA KUMAR JEYAPRAKASAM, PhD Center for Toxicology and Health Risk Studies (CORE) Faculty of Health Science (FSK) Universiti Kebangsaan Malaysia (UKM)  LECTURE OUTLINE Subtopic 1...

INTRODUCTION TO COCCIDIA & MALARIA 1 Dr. NANTHA KUMAR JEYAPRAKASAM, PhD Center for Toxicology and Health Risk Studies (CORE) Faculty of Health Science (FSK) Universiti Kebangsaan Malaysia (UKM)  LECTURE OUTLINE Subtopic 1 Subtopic 3 Subtopic 5 General introduction to Etiological agent of Pathogenesis and clinical Coccidia & malaria malaria features of malaria 1 3 5 2 4 Distribution & Life cycle of epidemiology of malaria malaria parasite Subtopic 2 Subtopic 4  INTRODUCTION TO COCCIDIA The main division of protozoa  INTRODUCTION TO COCCIDIA Unicellular Belong to Phylum Live intracellularly (at least during part of their protozoa Apicomplexa life cycle) Possess a structure called apical complex in at Found in body No specific locomotive least one stage of life (for attachment & fluid or tissue organelle penetration)  INTRODUCTION TO COCCIDIA Human parasite and All coccidian have a Complex life cycle also cause severe sexual sporogonic phase infection in usually involving > 1 & an asexual schizogonic hosts phase domesticated animals Definitive host usually All are parasitic Infections mainly zoonotic organisms produces oocysts INTRODUCTION TO COCCIDIA  Taxonomy Classifications Phylum Apicomplexa Order Eucoccidiorida Order Haemosporida Family Family Family Family Crytosporidiidae Eimeriidae Sarcocystidae Plasmodiidae Genus Genus Genus Genus Eimeria Toxoplasma Plasmodium Cryptosporidium Isospora Sarcocystis Haemoproteus Tyzzeria Coccidia are single-celled obligate intracellular protozoan parasites in the class Conoidasida within the phylum Apicomplexa. INTRODUCTION TO MALARIA CLASSIFICATION Malaria parasite belongs to: Phylum: Apicomplexa Class: Aconoidasida (Subclass: Coccidia) Order: Hemosporida Genus: Plasmodium. Plasmodium, a genus of parasitic protozoans of the sporozoan subclass Coccidia that are the causative organisms of malaria  DISTRIBUTION & EPIDEMIOLOGY Plasmodium vivax ▪ Predominant malaria parasite in most parts of the world. Plasmodium falciparum ▪ Most prevalent malaria species ▪ Mostly confined to the tropics and subtropics. ▪ Well known to be the fatal form of human malaria Plasmodium malariae ▪ In subtropical and temperate areas. ▪ Less frequently seen than P. vivax or P. falciparum. Plasmodium ovale ▪ Confined to West Africa. Plasmodium knowlesi (a monkey malaria) ▪ Distributed in Southeast Asia where the reservoir macaques are prevalent  This map shows an approximation of the parts of the world where malaria transmission occurs. Malaria is found depends mainly on climatic factors such as temperature, humidity, and rainfall Generally prevalent in warmer regions closer to the equator The highest transmission is found in Africa South of the Sahara and in parts of Oceania such as Papua New Guinea CDC 2020 https://www.cdc.gov/malaria/about/distribution.html A large number of human P. knowlesi infections were described in the Kapit Division of Sarawak in 2004. Annual reported malaria cases and deaths in Imported case: Malaria case Malaysia, 2000–2018 or infection in which the infection was acquired outside the area in which it is diagnosed. Introduced case: A case contracted locally, with strong epidemiological evidence linking it directly to a known imported case (first-generation local transmission) Indigenous case: A case contracted locally with no evidence of importation and no direct link to transmission from an imported case Chin et al. 2020 Distribution of Plasmodium knowlesi malaria cases by District-level hotspot and coldspot state in Malaysia, 2018 spatial clusters of knowlesi Chin et al. 2020 malaria (2011–2018). Phang et al. 2020  Knowlesi malaria cases in Southeast Asia Anopheles mosquitoes Macaca fascicularis Macaca nemestrina Presbytis melalophos The number and distribution of reported human infections with P. knowlesi, the limits of natural distribution of two species of macaques and the limits of natural distribution of mosquitoes of the An. leucosphyrus group (Cox-Singh & Singh 2008). Emergence of other zoonotic simian malaria infections in Malaysia & other neighboring countries Denmark traveler: Cambodia: P.cy (n=1) P.cy (n=11) Hartmeyer et al. P.cy + P.v (n=2) (2019) Imwong et al. (2019) Thailand: P.cy (n=21)* Sabah: P.in (n=19)* P.cy (n=2) P.fi (n=3)* Grignard et al. (2019) Putaporntip et al. (2021) Sarawak: P.cy + P.k (n=6) Terengganu: Raja et al. (2020) P.cy (n=1) Ta et al. (2014) P. Malaysia: Pahang: Detection of P. P.in (n=2) cynomolgi, P. inui, P. Liew et al. (2021) inui-like, P. coatneyi & P.simiovale in archived blood samples of indigenous people. Key: Pct = P. coatneyi, Pcy = P.cynomolgi, Pfi = P.fieldi, Pin = Yap et al. (2021) * Coinfection with other Plasmodium species P.inui, Pk = P.knowlesi  ETIOLOGICAL AGENT OF MALARIA Plasmodium falciparum: Malignant tertian malaria 48 hr Plasmodium vivax: Benign tertian malaria 48 hr Plasmodium ovale: Benign tertian malaria. 48 hr Plasmodium malariae: Benign quartan malaria 72 hr Plasmodium knowlesi: Quotidian malaria 24 hr  Malaria vectors Human malaria is transmitted by over 60 species of female Anopheles mosquito through the bite when blood meal is taken. The male mosquito feeds exclusively on fruits and juices, but the female mosquito needs blood meal, before the eggs can be laid. Eg: An. maculatus, An. balabacensis, An. dirus, An. letifer An. campestris, An. sundaicus, An. donaldi, An. leucophyrus and An. flavirostris Malaria and Anopheles mosquitos in Malaysia  A global map of dominant malaria vector species Dominant vector species/species complexes (DVS) per region https://parasitesandvectors.biomedcentral.com/counter/pdf/1 0.1186/1756-3305-5-69.pdf Simian malaria parasites of Southeast Asia: their Leucosphyrus Group natural vectors, hosts and geographical distribution (modified from Sallum et al.) Simian Malaria Parasites & Vectors Anopheles Leucosphyrus Group mosquitoes incriminated as vectors of Plasmodium knowlesi in Malaysia State Localities Vector References Hulu Selangor An. introlatus Vythilingam et al. 2014 Selangor Klang An. hackeri Wharton & Eyles 1961 Pahang Kuala Lipis An. cracens Vythilingam et al. 2008; Jiram et al. 2012 Sabah Kudat An. balabecensis Wong et al. 2015; Chua et al. 2017 Kapit An. latens Vythilingam et al. 2006; Tan et al. 2008 Sarawak Betong An. introlatus Ang et al. 2021 Lawas An. balabacensis Ang et al. 2020 Anopheles from the Umbrosus & Barbirostris Group mosquitoes incriminated as vectors of Plasmodium knowlesi in Malaysia State Localities Vector References Sabah Keningau An. donaldi Hawkes et al. 2019 Betong An. collessi Ang et al. 2021 Sarawak Betong An. roperi Ang et al. 2021 Lawas An. donaldi Ang et al. 2020 MODES OF TRANSMISSION 1. Bite of infected Anopheles mosquito 2. Blood transfusion 3. Organ transplant 4. Congenital transmission 5. Shared syringes 6. Zoonosis (Pk)  LIFE CYCLE OF THE PARASITES Malaria parasite passes its life cycle in two hosts: 1. Definitive host: Female Anopheles mosquito. 2. Intermediate host: Man. The life cycle of malarial parasite comprises of two stages- 1. an asexual phase (schizogony) occurring in humans, which act as the intermediate host and 2. a sexual phase (sporogony) occurring in mosquito, which serves as a definitive host for the parasite Exo-erythrocytic cycle During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host. Sporozoites infect liver parenchymal cells (hepatocytes) and mature into schizonts, which rupture and release merozoites. P. vivax and P. ovale do exhibit a dormant stage [hypnozoites] which can persist in the liver (if untreated) and cause relapses by invading the bloodstream weeks, or even years later. Erythrocytic cycle The parasites undergo asexual multiplication in the erythrocytes (erythrocytic schizogony ) after the liver stage. Merozoites infect red blood cells. The parasite feeds on the haemoglobin. It does not metabolize haemoglobin completely and leaves behind haemozoin or malaria pigment. The ring stage trophozoites mature into schizonts, which rupture releasing merozoites. Some parasites differentiate into sexual erythrocytic stages (gametocytes). Blood stage parasites are responsible for the clinical manifestations of the disease. The synchronised rupturing of infected RBC releasing merozoites, pigments and toxic materials gives rise to the paroxysm of malaria (febrile episodes). Schematic diagram showing formation of microgamete and macrogamete Sporogonic cycle The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested by an Anopheles mosquito during a blood meal. While in the mosquito’s stomach, the microgametes penetrate the macrogametes generating zygotes. The zygotes in turn become motile and elongated (ookinetes) which invade the midgut wall of the mosquito where they develop into oocysts. The oocysts grow, rupture, and release sporozoites, which make their way to the mosquito’s salivary glands. Inoculation of the sporozoites into a new human host perpetuates the malaria life cycle. Male gametocytes (microgametes) Ruptured Sporozoites + Zygote Ookinete Oocyst mature in salivary Female gametocytes (motile form) oocyst glands (macrogametes) Salivary glands & Sporozoites The salivary glands of the mosquito. (a) Schematic diagram of the salivary glands (WHO, 1975). (b) The salivary glands of field caught Anopheles mosquitoes from the study under 100x magnification and (c) the spindle-shaped sporozoites observed under 400x magnification (marked in red box). ML = Middle lobe; LL = Lateral lobes; CS = Salivary duct; CSC = Common salivary duct  Midguts & Oocysts Oocysts in the midgut of the mosquito. (a) Schematic diagram of oocysts on the midgut (WHO, 1975). (b) The presence of the oocysts (marked with red arrows) on the midgut of field caught Anopheles mosquitoes from the study under 100x and (c) 400x magnification.  PATHOGENESIS & CLINICAL FEATURES Clinical manifestations in malaria are caused by products of erythrocytic schizogony and the host's reaction to them: 1. The disease process in malaria occurs due to the local or systemic response of the host to parasite antigens and tissue hypoxia caused by reduced oxygen delivery because of obstruction of blood flow by the parasitized erythrocytes. 2. Hepatomegaly Kupffer cells are increased and filled with parasites. Hemozoin pigments are also found in the Parenchymal cells show fatty degeneration, atrophy and centrilobular necrosis. 3. Splenomegaly Spleen is soft, moderately enlarged, and congested in acute infection. In chronic infection, the spleen undergoes fibrosis and the sinusoids are dilated. 4. Hemoglobinuric nephrosis Kidneys are enlarged and congested. Glomeruli frequently contain malarial pigments and tubules may contain hemoglobin casts 5. Encephalopathy The brain in P. falciparum infection is congested. Capillaries of the brain are plugged with parasitized RBCs 5. Anaemia Anaemia is caused by rupture of infected red blood cells and other causes of anaemia are by complement-mediated, autoimmune haemolysis and hypersplenism. A decreased erythropoiesis in the bone marrow may also contribute to anaemia.  PATHOGENESIS (P. falciparum, Pf) Erythrocytic schizogony occurs in organ capillaries eg. Brain, heart, lungs, kidney Changes in the surface of infected erythrocytes whereby they become sticky and causing adhesion to one another (formation of rouleaux) and to the endothelium of vessels causing congestion and blockade to blood flow leading to tissue hypoxia High level of parasitemia because it infects RBC of all ages (250,000- 300,000/ul blood or >5% parasitaemia)  Pf is the only human malaria parasite that produces microvascular disease As Pf parasites mature, knobs appear on the surface of the parasitized red cell that facilitate cytoadherence of Pf parasitized RBC to endothelial cells in capillaries and post capillary venules of brain, kidney etc. Cytokines such as TNF is increased by the infection and it enhances cytoadherence worsening microvascular pathology CLINICAL FEATURES The typical clinical feature of malaria consists of periodic bouts of fever with chill and rigor, followed by anemia, splenomegaly and hepatomegaly. The classic febrile paroxysm comprises of three distinct stages- 1. Cold stage 2. Hot stage and 3. Sweating stage. CLINICAL FEATURES COLD STAGE: ▪ chills & rigors ▪ peripheral blood vessels constrict ▪ lips & nails cyanotic ▪ at the end of cold stage body temp begins to rise rapidly ▪ headache and nausea This stage lasted about 15 mins to 1 hr CLINICAL FEATURES WARM/HOT STAGE: ▪ Temp peaks at 39-41 °C ▪ Feel intensely hot ▪ Blood vessels dilate ▪ Skin warm and face flushed ▪ Headache, vomiting, convulsion may occur esp. children This stage lasted about 6 to 12 hr. CLINICAL FEATURES SWEATING/PROFUSE STAGE: ▪ temp falls, ▪ feels exhausted ▪ skin cool and moist ▪ usually falls asleep to wake up refreshed ▪ later feels better and well CLINICAL FEATURES Typically characterised by paroxysms of febrile episodes which occur at regular intervals The paroxysm usually begins in the early afternoon and lasts for 8-12 hours. The febrile paroxysm synchronizes with the erythrocytic schizogony. The periodicity are approximately 48 hrs (tertian) for P. v, P.f and P.o, and 72 hrs (quartan) for P.m The malarial paroxysm occurs at the end of the schizogonic cycle, when merozoites of the mature schizonts, together with their pigments and residual erythrocyte debris are poured into the circulation CLINICAL FEATURES Quotidian periodicity with fever occurring at 24 hour intervals ▪ may be due to two broods of tertian parasites maturing on successive days or ▪ due to mixed infection.  CLINICAL DIFFERENCES BETWEEN MALARIA SPECIES P.v P.m P.f P.o P.k Name benign quartan malignant benign simian tertian tertian tertian quotidian Incubation 14 (12-17 28 (18-40 12 (8-14 days) 14 (8-31 9-12 period days) days) days) Erythro 48 72 48 48 24 cycle Relaps yes no no yes no Parasi- 20,000 6,000 300,000 9,000 > 100K taemia /ul CLINICAL DIFFERENCES BETWEEN MALARIA SPECIES  Dr. NANTHA KUMAR JEYAPRAKASAM, PhD Center for Toxicology and Health Risk Studies (CORE) Faculty of Health Science (FSK) Universiti Kebangsaan Malaysia (UKM)