Readings-Lecture 9 • Ch.8 (p. 163 [table 8.2], pp. 167- 172, special attention to tables) Lecture 9: Emerging Parasitic • Ch. 11 (pp. 283-86) Protozoa pt. 2 (Apicomplexans-2: , ) • Ch. 14 (pp. 365, 375, 377) Presented by: Matt Tucker, M.S., MSPH [email protected]

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Monsters Inside Me Learning Objectives

• Malaria ( spp., Apicomplexan): • Understand the enormous impact malaria has on global health • Know the various species of Plasmodium that can infect man, and differences Background: http://animal.discovery.com/invertebrates/monsters- between them. inside-me/malaria-plasmodium/ • Identify populations that are especially at risk for malaria and • Understand the various facets of malaria that make it difficult to eradicate Video: http://animal.discovery.com/videos/monsters-inside-me- • Know the general life cycles of malaria and Babesiosis-sources of , malaria-parasite.html infective/diagnostic stages, hosts. How are these cycles different from other parasitic protozoa? For malaria, know key diagnostic differences between P. Babesiosis (Babesia spp., Apicomplexan): falciparum and P. vivax • Be familiar with antimalarial drug resistance and where it is a major problem. Background: http://animal.discovery.com/invertebrates/monsters- What drugs are failing in the world and what are viable alternatives? inside-me/babesiosis-babesia/ • Know aspects of malaria and babesia that make them emerging diseases • Describe why vaccines for malaria are elusive Video: http://animal.discovery.com/videos/monsters-inside-me- babesiosis.html

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Lecture 9: On the Menu Malaria

• pt. 2 – Class , Order . Plasmodium spp. – Class Aconoidasida, Order Piroplasmida . Babesia spp.

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1 Malaria Intro Video Malaria: Background

• http://video.nationalgeographic.com/video • Malaria is the most important parasitic disease affecting man /player/science/health-human-body- • Disease of antiquity sci/health/malaria-sci.html – First described in Chinese writings in 2700 B.C. • Approximately 156 species of Plasmodium which infect various species of vertebrates. – Four species are considered true parasites of humans (int. ) • Transmitted by Anopheles mosquitoes (def. host)

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Public Health Impact Plasmodium spp. Facts

• World Health Organization estimates • P. vivax • P. malariae – About 3.3 billion people are at risk of malaria – Most common, except in Africa – Global, but patchy 72h cycle – 270 million new per year – Temperate and tropical • P. ovale – 1-2 mil children die per yr – 48h cycle, relapse, hypnozoites, – 90% of deaths occur in Africa (south of Sahara) – Mainly in tropical Africa and drug resistance Oceania • Occurs in tropical and temperate regions worldwide • P. falciparum – 48h cycle, relapse • Most cases in Africa, followed by Asia and South – Tropical America • P. knowlesi – Holoendemic in much of Africa – New emerging species in • Dependent upon and host, other factors – 48h cycle, mortality, Tropical regions, humans • Global “contraction” from 1900-1950 and drug resistance – Malaysia, 24 h. cycle accelerated during 1950-1965 – Most lethal

Malaria: Life cycle Worldwide distribution of malaria: 2009

Mosquito is definitive host

Man is intermediate host

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2 Who does malaria affect? Malaria – the cost

• Infants & young children (under 5 yrs. old) • Africa’s GDP today would be up to 32 percent greater if malaria had been eliminated 35 years ago. • Non-immune pregnant women • Malaria- countries are among the world’s most impoverished. – High rates of miscarriage and cause over 10% of maternal • In Thailand, malaria patients pay nine times their average daily wage for deaths (soaring to a 50% death rate in cases of severe care. disease) annually. • A malaria-stricken family spends an average of over one quarter of its • Semi-immune pregnant women risk severe anemia and income on malaria treatment, as well as paying prevention costs and impaired fetal growth even if they show no signs of suffering loss of income. acute disease. • Malaria-afflicted families on average can only harvest 40% of the crops harvested by healthy families – 200,000 of their infants die annually as a result of malaria • Children experiencing cerebral malaria and malaria accompanied by infection during pregnancy. complex seizures • HIV-infected pregnant women are also at increased risk. – 24% of children in both malaria groups had significant cognitive impairment. • Non immune (tourist) – Crude estimates: 128,000 children a year develop epilepsy following malaria. – 250,000 develop significant cognitive impairment

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Why is it getting worse? Mosquitoes and Malaria

Anopheline Mosquitoes • Approximately 430 known species, 30-50 transmit • Substandard, counterfeit drugs malaria • Life cycle – 7 to 20 days (egg to adult) • Drug resistance – Females mate once and lay 200-1000 eggs in 3-12 batches over a lifetime – Find their host by chemical and physical stimuli • Insecticide resistance – Average life span of adult mosquito < 3 week

• Deterioration of public health services Malaria development • Development in mosquito (extrinsic incubation • Environmental changes period)=7 to 12 days • Each male & female gametocyte produce >10,000 • No vaccine sporozoites • Important vector species begin entering houses in the early evening, often at sunset. • Important vector species often begin leaving houses just before or during sunrise.

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Ecology and malaria Distribution of malaria vectors

• Determines presence of larval habitats and abundance of vectors • Influences distribution and abundance of humans (mosquito- human-mosquito cycle of transmission) • Factors that influence presence, abundance and longevity of mosquitoes. – Temperature – Rainfall – Relative Humidity – Topography . Altitude, elevation . Soil Type . Land cover (vegetation)

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3 Malaria: 1900-2002 Malaria in the U.S.

• Malaria was endemic in the US until the late 1940's. • Most of the transmission occurred in the southeastern states. • Control efforts conducted by the state and local health departments, supported by the federal government, resulted in the disease being eradicated by 1949. • Such measures included drainage, removal of mosquito breeding sites, and spraying (occasionally from aircrafts) of insecticide

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Malaria in the United States Recent Stats

• Constant risk of reintroduction to U.S. • Between 1957-2003, in the United States, 63 outbreaks of locally transmitted mosquito- borne malaria have occurred • Local mosquitoes become infected by biting persons carrying malaria parasites (acquired in endemic areas) and then transmit malaria to local residents

• 11 outbreaks involving 20 cases of probable locally acquired mosquito-transmitted malaria have been reported to CDC since 1992 – Palm Beach County, FL. . 1996: 2 outbreaks . July-August 2003: 7 cases of locally acquired P. vivax

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Minimizing Risk of Re-emerging Plasmodium knowlesi malaria in U.S.

• Prevention of malaria in travelers • Infects long-tailed macaques • Ensure prompt diagnosis and treatment of • Previously diagnosed as P. malariae in all infected persons humans • Containment of local outbreaks of malaria • 24 hour cycle, higher parasitemia than P. malariae • Conduct surveillance of malaria cases • Exists primarily in Malaysia • Sensitize local communities to the risk of • 2008 study: P. knowlesi DNA was detected in malaria 27.7% samples from Sarawak hospitals, • Encourage personal protection measures 83.7% from Sabah, 5 from Pahang to prevent mosquito bites • Similar infections have been found in • Conduct vector control activities Thailand, the Philippines, and Singapore • Economic exploitation of the forest is • During 1963-1999, 93 cases of perhaps bringing monkeys, mosquitoes and transfusion-transmitted malaria were humans into increased contact. reported in the United States

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4 P. knowlesi: Emerging Disease MALARIA: Prodromal symptoms

• The first symptoms of malaria after the pre-patent period (period between inoculation and detectable stages: when the sporozoites undergo schizogony in the liver) are called the primary attack. It is usually atypical and may resemble any febrile illness.

• Headache • Feeling of weakness and exhaustion • Aching in bones, limbs, or back • Loss of appetite • Desire to stretch or yawn • Nausea and vomiting

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Prepatent & incubation periods of Uncomplicated Malaria human malaria • The asexual intra-erythrocytic stage causes all pathophysiological processes PREPATENT PERIOD – Parasite and red cell material released with schizont rupture, resulting in chills and high grade fever. • Paroxysms P. falciparum 11 - 14 days 8 - 15 days – Episodes of chills and fever – Begins with cold stage of up to 1 hr duration-Profuse sweating as body P. vivax 11 - 15 days 12 - 20 days temperature falls – Fever stage follows rapidly for 6-12 hr P. ovale 14 - 26 days 11 - 16 days . Nausea, Vomiting, Rapid pulse • The pattern of intermittent chills/fever mirrors the synchronized parasite P. malariae 3 - 4 weeks 18 - 40 days development in an infected person’s blood (48 or 72 hours) – Benign tertian: P. vivax – Malignant tertian : P. falciparum – Quartan : P. malariae • Recrudescences= reinfection as result of parasites not being cleared • Relapses= result of P. vivax and P. ovale stages that hide in liver

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Severe Malaria and other manifestations P. falciparum- Cerebral malaria

• Cerebral malaria, with abnormal Severe disease with life-threatening • Most common clinical presentation of severe behavior, impairment of consciousness, complications- P. falciparum convulsions, seizures, coma, or other • Hypoglycemia malaria in man neurologic abnormalities • Severe anemia due to hemolysis • Septicemia • Definition (destruction of red blood cells) • Gastrointestinal bleeding – Parasitized red blood cells (PRBCs) adhere to the • Hemoglobinuria (hemoglobin in the urine) • Pneumonia due to hemolysis (Blackwater fever), renal cerebral microvasculature, causing blockage of the failure blood's pathway - stops blood flow, leading to a • Pulmonary edema or acute respiratory • The clinical presentation can vary shortage of oxygen and nutrients those areas of the distress syndrome (ARDS) substantially depending on the brain (hypoxia). • Abnormalities in blood coagulation and infecting species, the level of thrombocytopenia (decrease in blood – Unrousable coma platelets)-bleeding/clotting disorders parasitemia, and the immune status of • Cardiovascular collapse and shock the patient. – Other causes of encephalopathy have been excluded • Metabolic acidosis (viral infections, head injury, etc) • Hyperparasitemia Don’t memorize, but know spectrum of – Mortality rate of ~22% despite treatment severity and how different from uncomplicated malaria

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5 Pregnancy and Malaria Diagnosis: Important facts

Thick and thin blood smears • In sub-Saharan Africa, there are 400,000 cases of severe • Elicit a good travel history maternal anemia and 75,000-200,000 infant deaths annually. • Ethnic origin of patient or family – 10,000 maternal deaths per year. members • History of previous episodes of malaria • Adverse effects on both mother and fetus, including maternal • anemia, fetal loss, premature delivery, intrauterine growth Blood transfusions or i.v. drug use retardation, and delivery of low birth-weight infants. • Occupation • Giemsa stained blood smears • It is a particular problem for women in their first and second • PCR pregnancies and for women who are HIV-positive. • Dipstick antibody tests to differentiate • High transmission area vs. low transmission area: anemia and species birth outcomes differ • DNA staining

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Ring stages Gametocyte Diagnostic criteria P. falciparum vs. P. vivax

P. falciparum Notice the differences? • Mostly rings or gametocytes present – Trophozoites and schizonts cytoadherence • Crescent shaped gametocytes • 24 to 36 merozoites (if schizont present) • No Schuffner’s stippling • Infected erythrocyte not enlarged • All stages present • Infected erythrocyte enlarged • Schuffner’s stippling (dots) • 12 to 24 merozoites • Oval gametocyte almost fills erythrocyte

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P. falciparum Adhesion and Disease Antimalarial Treatment

• P. falciparum -only immature, ring forms circulate in the peripheral blood • Treatment varies according to the infecting species, the geographic • Mature erythrocytic forms (trophozoites and area where the infection was acquired, and the severity of the disease schizonts) bind to vascular endothelium through • Treatment for malaria should not be initiated until the diagnosis has ’knobs’ that enable them to be sequestered in the venules and avoid elimination by the spleen. been confirmed by laboratory investigations. • Cerebral malaria • Treatment of infection • Rosetting – Acute, uncomplicated malaria – Erythrocytes infected with mature asexual parasites – Severe or cerebral malaria adhere to uninfected erythrocytes • Radical cure – Possible involvement in pathophyiology of severe disease • Prophylaxis – Causal, Suppressive • Placenta and parasite adhesion – Post-exposure – Large numbers of infected erythrocytes sequestered • Intermittent Presumptive Treatment (IPT) on the maternal side of the placenta. • Pfemp1, antigenic variation- mech for avoiding – Infants (IPTi) Immune Reponse – Pregnancy (IPTp)

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6 Treatment: Severe Malaria Treatment- Cerebral Malaria

• Choose appropriate antimalarial drug and • Quinine, intravenous – Slow infusion avoids cardiovascular toxicity and route of administration hypoglycemia • Follow blood glucose carefully • Quinidine gluconate, intravenous – Very effective, but adverse cardiac events • Administer I.V. fluids for shock and • Artemisinin derivatives hypovolemia – Rapidly acting – Several derivatives and formulations • Administer oxygen by nasal catheter . Artesunate drug of choice for severe disease – Compassionate use IND in US (via CDC) • Consider replacing erythrocytes for – >30% more effective than quinine in preventing death in cerebral malaria hematocrit of 30 or parasitemia > 10%

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Problems with antimalarial drugs Time to Development of Resistance to Antimalarial Drugs

DRUG PROBLEMS Chloroquine Artemisinin Recrudescence, Neurotoxicity 16 years Atovaquone Resistance Azithromycin Limited efficacy Fansidar Chloroquine Resistance 6 years Doxycycline Phototoxicity, GI intolerance Fansidar Resistance, Allergic Rxns Mefloquine Halofantrine Cardiotoxicity 4 years Mefloquine Resistance, Psychiatric effects Atovaquone Primaquine Therapeutic Index, Resistance? 6 months Proguanil Resistance, Mouth ulcers Quinidine gluconate Going off the market? Quinine Resistance, Tinnitus 1940 1950 1960 1970 1980 1990

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Spread of chloroquine resistant Chloroquine (CQ) Plasmodium falciparum

• Discovered during WW II • Effective against all Plasmodium spp. • CQ is trapped in the parasite food vacuoles where it is toxic – Inhibits polymerization of hemazoin and free heme kills the parasite • ‘Magic bullet’ that was basis of 1960s malaria eradication campaign • Resistance first emerged in early ’60s in S. America and SE Asia – Resistance conferred by complex mutations in a Plasmodium falciparum chloroquine resistance transporter gene (pfcrt) – Big problem in Africa, Asia

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7 Mefloquine (Lariam)

• Prophylaxis - in CQ & multi-drug resistant regions • Treatment - in CQ & multi-drug resistant regions – Combined with artesunate to treat mefloquine resistant malaria in SE Asia – For P. vivax or P. falciparum

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Artemisinin (Qinghaosu) Artemisinin Treatment of Malaria

• Rapid relief from symptoms and fast clearance times • Harvested from the Chinese herb • Artemesia annua (sweet wormwood) Broad stage specificity with gametocidal activity • Cheap alternative to other drugs • Many derivatives • Not recommended for prophylaxis because of short • 200 BC-China: recognized as herbal elimination time remedy of hemorrhoids and fever • Animal studies: neurotoxicity at high doses and also death of • 1972 identified as active constituent embryos, and morphological abnormalities in early pregnancy of Artemesia annua • Can be combined with other drugs for effective treatment • 1999 Artemisinin combination O O (ACT) therapy (ACT) O • Only treatment for severe malaria besides quinine O • Resistance not reported O

C15H22O5

So, how do you correctly treat a Artemisinin Combination Therapy (ACT) patient? • WHO issued new guidelines on malaria treatment and requested pharmaceutical companies to end the marketing and • Treatment of depends on many factors including disease sale of "single-drug" artemisinin malaria medicines, in order to severity, the species of malaria parasite causing the infection, prevent malaria parasites from developing resistance to this and the part of the world in which the infection was acquired. drug (1-20-06 Press release). – Planning, Case history very important • The artemisinin component • Think about the probability that the organism is resistant to – Reliably efficacious, rapidly effective certain antimalarial drugs. • Partner drug(s) • Additional factors such as age, weight, and pregnancy status may limit the available options for malaria treatment. – Ensures high cure rate • – Protects artemisinin Guidelines for U.S. Travelers – – Very well tolerated http://www.cdc.gov/malaria/diagnosis_treatment/treatment.html – No resistance Interactive world map for malaria /risk: – Reduces gametocyte carriage http://apps.who.int/tools/geoserver/www/ith/index.html – Reduces de-novo resistance to partner – Prophylactic activity CDC list of malaria countries and risk: http://wwwnc.cdc.gov/travel/yellowbook/2010/chapter- 2/malaria-risk-information-and-prophylaxis.aspx HSC4933. Emerging Infectious Diseases 48

8 Prevention and Control of Malaria Prevention During Pregnancy

• Reduce the transmission of • Intermittent preventive treatment (IPT)-antimalarial treatment the disease by mosquito given at regular intervals during pregnancy, control – Two to three doses of sulfadoxine-pyrimethamine (SP) administered • Mosquito nets treated with to a pregnant woman through antenatal care services. This protects long-lasting insecticide, a pregnant women from possible death and anemia and also very cost-effective method prevents malaria-related low birthweight in infants • Indoor residual spraying of • Insecticide-treated bed nets (ITN), indoor residual spraying insecticides. • Febrile malaria case management. • Repellents • Malaria prevention is particularly challenging in HIV-infected • Drugs- all groups- kill women, who might constitute up to 40% of the antenatal parasites population in southern Africa. • Vaccines -block infection, kill – HIV-infected pregnant women are more likely to fail antimalarial parasite treatment and require three or more doses of IPTp • Pregnant women

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Vaccines Control: Mechanisms and Challenges

• Pre-erythrocytic stages- directed against • Requires an integrated approach sporozoites and/or liver stages (prevent – Vectors blood-stage infection) – Proper antimalarial drugs • Against asexual blood stages are designed to reduce clinical severity – Access to prompt, medical treatment • Against mosquito stages are designed to • Factors contributing to disease halt development in the mosquito – Reservoir-prevalence in humans (transmission-blocking vaccines)- – Vector-suitability of local anopheline as hosts-breeding • Best vaccine candidate: RTS,S vaccine preferences, flight/resting behavior, abundance, temp., rainfall, (pre-erythrocytic)- up to 50% protection in humidity, clinical trials (in stage three clinical trials, – New hosts-nonimmune hosts now) – Local climattic conditions • Major problem: antigens are constantly changing and developing a vaccine against • Local geographical and hydrogeographical conditions, human these varying antigens is very difficult activities that can determine availability of and accessibility to mosquito breeding areas

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Genetic engineering and Malaria Babesia spp.

• Zoonotic disease maintained by the interaction • Transgenic mosquitoes of vectors, transport hosts, and animal – Mosquitoes refractory to mouse reservoirs. malaria in lab experiments- transgenic • More than 100 species have been reported, only malaria-resistant mosquitoes have a a few have been identified as causing human selective advantage over infections. nontransgenic mosquitoes? Blocking transmission of sporozoites through the gut wall and into the • and have been – Sterile male mosquitoes released into salivary glands. a given environment identified in most human cases – Male mosquitoes carrying lethal • of the family Ixodidae transmit B. microti genes causing death of newborns very (and Lyme disease). young • Transplacentally or perinatally acquired – Disadvantages: (congenital) babesiosis have been reported. . Could resistant mosquitoes be useful in • Blood transfusions-emerging problem the wild? They must survive better than non-resistant mosquitoes even when not exposed to malaria. . Not shown to work in Plasmodium falciparum

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9 Life Cycle: Babesia Geographic Distribution

• Worldwide, but little is known about the prevalence of Babesia in malaria-endemic countries, where misidentification as Plasmodium probably occurs. • Endemic areas are regions of tick habitat, including the forest regions of the Northeastern U.S. and temperate regions of Europe. • In Europe, most reported cases are due to B. divergens and occur in splenectomized patients. • In the U.S., B. microti is the agent most frequently identified (Northeast mostly, less common in Midwest), and can occur in nonsplenectomized individuals. • High number of asymptomatic infections • The first U.S. case of babesiosis was reported on Nantucket Island in 1966. Between 1968 and 1993, more than 450 cases of Babesia infections were confirmed in the United States. – An increasing trend over the past 30 years may be the result of restocking of the deer population, curtailment of hunting, and an increase in outdoor recreational activities.

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Disease, dx, tx Babesia and blood transfusion: U.S.

• Fever, chills, sweating, myalgias, fatigue, • Since 1979,over 80 cases of transfusion-associated babesiosis have been hepatosplenomegaly, and hemolytic anemia. reported in the US (FDA) • Symptoms typically occur after an incubation period of • Currently, the blood supply is not screened for Babesia 1 to 4 weeks, and can last several weeks. The disease is • Donors are deferred if they have a fever at the time of donation or report a more severe in patients who are immunosuppressed, history of Babesia infection, but this practice alone is unable to prevent splenectomized, and/or elderly. asymptomatic individuals with low levels of parasitemia from serving as donors. • Infections caused by B. divergens tend to be more severe (frequently fatal if not appropriately treated) than those due to B. microti, where clinical recovery usually occurs.

Laboratory Diagnosis: • Microscopic examination of thick and thin blood smears stained with Giemsa. • Seven cases of transfusion-associated babesiosis have been identified among • Isolation of the organisms by inoculation of patient blood into hamsters or gerbils New York City (NYC) residents since September 2008; this is a notable increase • Treatment: Clindamycin plus quinine or atovaquone over baseline as previously an average of one to two transfusion-associated plus azithromycin cases were reported annually;

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Prevention

• Avoid tick exposures – Tick infested areas (high tick season between May and September) – Cover skin with light clothing, searching for ticks after being outdoors and removing discovered ticks from the skin. – Applying bug repellent with DEET

• Eradication? – Preventative measures seem to be more recommended over vector control. – Due to the relatively low prevalence of the disease and the presence of several reservoirs, Babesiosis is currently not a candidate for vaccine prevention.

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