Parasitic neuro infections

Parasitic infections affecting central nervous system

1. PARASITIC NEURO INFECTIONS PRESENTED BY: MISS. SHWETA SHARMA M.SC. NURSING 2 nd YEAR AIIMS JODHPUR

2. CASE May, a 4-year old female, is fond of playing. She and her playmates play anywhere they could reach, with anything they could find. When May arrives home, she immediately reaches for the snacks on the table without washing her hands. Weeks after, her mother noticed that May keeps on scratching her anal area, especially at night. She brought May to the community health center, where the community health nurse performed a test she called the scotch tape swab test. When the doctor arrived, May and her mother were told that May has enterobiasis or pinworm infection. 31-10-2020 2

3. INTRODUCTION Parasites are a diverse group of organisms that can be broadly classified into single-celled organisms (i.e. protozoa) or multicellular helminths. Parasitic diseases of the central nervous system are associated with high mortality and morbidity. The burden of these diseases is amplified as survivors are often left with neurologic symptoms affecting mobility, sensory organs, and cognitive functions, as well as seizures/epilepsy. 31-10-2020 3

4. These diseases lead to suffering by causing lifelong disabilities, reducing economic productivity, and causing social stigma. The complexity of parasitic life cycles and geographic specificities, as well as overlapping clinical manifestations in the host reflecting the diverse pathogenesis of parasites, can present diagnostic challenges. 31-10-2020 4

5. PARASITIC INFECTIONS OF THE CENTRAL NERVOUS SYSTEM • Neurocysticercosis • Toxoplasmosis • Echinococcosis ( hydatidosis ) • Schistosomiasis • Paragonimiasis • Cerebral malaria- Severe falciparum malaria • Toxocariasis • Onchocerciasis • American trypanosomiasis (Chagas disease) • Human African trypanosomiasis (sleeping sickness) • Angiostrongyliasis 31-10-2020 5

6. Neurocysticercosis Result of accidental ingestion of eggs of Taenia solium (i.e., pork tapeworm), usually due to contamination of food by people with taeniasis. In developing countries, neurocysticercosis is the most common parasitic disease of the nervous system and is the main cause of acquired epilepsy. 31-10-2020 6

7. Epidemiology NCC predominantly affects adults in their third and fourth decade of life, and is relatively uncommon in children and the elderly. Most paediatric patients have a single transitional cyst that resolves spontaneously over a few months. 31-10-2020 7

8. Causes Eating undercooked pork from a pig with the infection Consuming water that contains the parasite Having poor hygiene 31-10-2020 8

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10. Clinical manifestations The clinical manifestations of NCC are heterogeneous and depend mainly on the localization of cysts and immune response by the host. Seizures, headache, focal deficits and cognitive abnormalities are the most frequent manifestations of cysts in the brain parenchyma. Extra parenchymal disease occurs in about one-third of patients with NCC (life-threatening). 31-10-2020 10

11. Acute hydrocephalus related to intraventricular cysts, or chronic hydrocephalus because of arachnoiditis or ependymitis. Spinal cord cysticercosis - rare - nerve root pain or spinal cord compression syndromes, according to the level of the lesion. Massive infection of striated muscles can cause generalized weakness associated with muscle pseudohypertrophy. 31-10-2020 11

12. Medical management Albendazole with corticosteroids Praziquantel (alternative to albendazole) with corticosteroids Combined albendazole/praziquantel with corticosteroids if >2 active parenchymal cysts 31-10-2020 12

13. Toxoplasmosis Toxoplasmosis is a disease that results from infection with the Toxoplasma gondii parasite, one of the world's most common parasites. Infection usually occurs by eating undercooked contaminated meat, exposure from infected cat faeces , or mother-to-child transmission during pregnancy. 31-10-2020 13

14. Epidemiology Globally, 1,90,100 annual cases of congenital toxoplasmosis have been reported, leading to 1.20 million DALYs (Disability adjusted life years) and 1.5 cases of congenital toxoplasmosis per 1000 live births. In India, 56,737-176,882 children are born with a possible risk of congenital toxoplasmosis every year. Seroprevalence of 22% in pregnant women was reported. 31-10-2020 14

15. Risk factors HIV/AIDS Chemotherapy Steroids or other immunosuppressant drugs 31-10-2020 15

16. Causes Toxoplasma gondii (T. gondii) is a single-celled parasitic organism that can infect most animals and birds. Because T. gondii infectious organisms are excreted only in cat faeces , wild and domestic cats are the parasite's ultimate host. One can become infected if he/she: • Come into contact with cat faeces that contain the parasite. • Eat or drink contaminated food or water. • Use contaminated knives, cutting boards or other utensils. • Eat unwashed fruits and vegetables. • Receive an infected organ transplant or transfused blood. 31-10-2020 16

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18. Pathophysiology After ingestion of the organism, Toxoplasma gondii cysts may develop in any tissue, but most commonly develop in the brain, retina, skeletal muscle and cardiac muscle. Rupture of the cysts releases the free tachyzoite, which causes acute illness. Fever, rash, lymphadenopathy and eye disturbances are typical in early stages. When lesions are in the CNS of immunocompromised patients, fever, headaches, confusion and seizures are common, as well as ocular disease (retinochoroiditis); however, many infections are subclinical, and 20% of HIV-infected patients with toxoplasmosis develop encephalitis. 31-10-2020 18

19. The disease may also be transmitted trans-placentally and have devastating effects on the fetal brain because maternal antibodies passed to the child will be limited by the blood–brain barrier. Seizures, microcephaly and chorioretinitis have been noted in most of these cases. 31-10-2020 19

20. Symptoms • Body aches • Swollen lymph nodes • Headache • Fever • Fatigue 31-10-2020 20

21. In people with weakened immune systems: Headache Confusion Poor coordination Seizures Lung problems that may resemble tuberculosis or Pneumocystis jiroveci pneumonia, a common opportunistic infection that occurs in people with AIDS Blurred vision caused by severe inflammation of your retina (ocular toxoplasmosis) 31-10-2020 21

22. Medical management Sulfadiazine + pyrimethamine with leucovorin Clindamycin (or atovaquone) + pyrimethamine with leucovorin (alternative) Trimethoprim-sulfamethoxazole (alternative) 31-10-2020 22

23. Complications Eye infections. Untreated, these infections can lead to blindness. Seizures and life-threatening illnesses such as encephalitis — a serious brain infection. Children with congenital toxoplasmosis may develop disabling complications, including hearing loss, mental disability and blindness. 31-10-2020 23

24. Prevention Wear gloves when gardening or handling soil. Wear gloves whenever working outdoors and washing hands thoroughly with soap and water afterward. Don't eat raw or undercooked meat. Meat, especially lamb, pork and beef, can harbour toxoplasma organisms. Wash kitchen utensils thoroughly . Wash hands after handling raw meat. 31-10-2020 24

25. Wash all fruits and vegetables . Remove peels when possible, but only after washing. Don't drink unpasteurized milk . Unpasteurized milk and other dairy products may contain toxoplasma parasites. Cover children's sandboxes to keep cats from using it as a litter box. 31-10-2020 25

26. For cat lovers • Keep cat healthy . Keep cat indoors and feed it dry or canned cat food, not raw meat. • Avoid stray cats or kittens. Most cats don't show signs of T. gondii infection, and although they can be tested for toxoplasmosis, it may take up to a month to get the results. • Have someone else clean cat's litter box. If that's not possible, wear gloves and a face mask to change the litter. Then wash hands well. Change the litter daily so that excreted cysts don't have time to become infectious. 31-10-2020 26

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28. Echinococcosis ( hydatidosis ) Echinococcosis is a parasitic disease of tapeworms of the Echinococcus type. The parasites Echinococcus granulosus and Echinococcus multilocularis causing cystic echinococcosis and alveolar echinococcosis , respectively, belong to the same genus; however, these pathologies are entirely different entities in terms of clinical manifestations, course of disease and prognosis. 31-10-2020 28

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30. Epidemiology In regions where cystic echinococcosis is endemic, incidence rates in humans can exceed 50 per 100 000 person-years. More than 1 million people are affected with echinococcosis at any one time. 31-10-2020 30

31. Cause The worm has a life cycle that requires definitive hosts and intermediate hosts. Definitive hosts are normally carnivores such as dogs, while intermediate hosts are usually herbivores such as sheep and cattle. Humans function as accidental hosts, because they are usually a dead end for the parasitic infection cycle. Humans are infected through ingestion of parasite eggs in contaminated food, water or soil, or after direct contact with animal hosts. 31-10-2020 31

32. Pathophysiology The infection may be primary or secondary to the spontaneous or traumatic rupture of a primary cerebral cyst or because of embolization of cardiac cysts. Cysts may remain asymptomatic until they are large enough to cause a mass effect. Cerebral lesions occur in 1–4% of individuals with cystic echinococcosis, with nonspecific clinical findings related to those of space occupying lesions, increased intracranial pressure and seizure activity. 31-10-2020 32

33. Clinical manifestations Cystic echinococcosis / hydatid disease Liver- abdominal pain, nausea and vomiting Lung - chronic cough, chest pain and shortness of breath. Other signs depend on the location of the hydatid cysts and the pressure exerted on the surrounding tissues. Anorexia, weight loss and weakness 31-10-2020 33

34. Alveolar echinococcosis Characterized by an asymptomatic incubation period of 5–15 years and the slow development of a primary tumour -like lesion which is usually located in the liver. Weight loss, abdominal pain, general malaise and signs of hepatic failure. Larval metastases may spread either to organs adjacent to the liver (for example, the spleen) or distant locations (such as the lungs, or the brain) following dissemination of the parasite via the blood and lymphatic system. If left untreated, alveolar echinococcosis is progressive and fatal. 31-10-2020 34

35. Medical management Albendazole or mebendazole (alone or with surgery) Prevention Prevent dogs from feeding on the carcasses of infected sheep. Control stray dog populations. Restrict home slaughter of sheep and other livestock. Do not consume any food or water that may have been contaminated by fecal matter from dogs. Wash hands with soap and warm water after handling dogs, and before handling food. Teach children the importance of washing hands to prevent infection. 31-10-2020 35

36. Schistosomiasis Schistosomiasis, also known as snail fever and bilharzia, is a disease caused by parasitic flatworms called schistosomes. 31-10-2020 36

37. Epidemiology Schistosomiasis is prevalent in tropical and subtropical areas, especially in poor communities without access to safe drinking water and adequate sanitation. It is estimated that at least 90% of those requiring treatment for schistosomiasis live in Africa. It affects about 200 million people worldwide. 31-10-2020 37

38. Cause People are infected during routine agricultural, domestic, occupational, and recreational activities, which expose them to infested water. Lack of hygiene and certain play habits of school-aged children such as swimming or fishing in infested water make them especially vulnerable to infection. 31-10-2020 38

39. Infection and transmission People become infected when larval forms of the parasite – released by freshwater snails – penetrate the skin during contact with infested water. Transmission occurs when people suffering from schistosomiasis contaminate freshwater sources with their excreta containing parasite eggs, which hatch in water. 31-10-2020 39

40. In the body, the larvae develop into adult schistosomes. Adult worms live in the blood vessels where the females release eggs. Some of the eggs are passed out of the body in the faeces or urine to continue the parasite’s lifecycle. Others become trapped in body tissues, causing immune reactions and progressive damage to organs. 31-10-2020 40

41. 5 Egg morphology of Schistosoma 31-10-2020 41

42. Symptoms Intestinal - abdominal pain, diarrhoea , and blood in the stool. Liver enlargement, ascites and portal hypertension and spleenomegaly . The classic sign of urogenital schistosomiasis is haematuria (blood in urine). Fibrosis of the bladder and ureter, and kidney damage are sometimes diagnosed in advanced cases. Bladder cancer is another possible complication in the later stages. 31-10-2020 42

43. In women, urogenital schistosomiasis may present with genital lesions, vaginal bleeding, pain during sexual intercourse, and nodules in the vulva. In men, urogenital schistosomiasis can induce pathology of the seminal vesicles, prostate, and other organs. Infertility Children - anaemia , stunting, reduced ability to learn, although the effects are usually reversible with treatment. 31-10-2020 43

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45. Medical management Praziquantel (after starting corticosteroid treatment) Prevention and control Large-scale treatment of at-risk population groups Access to safe water, improved sanitation, hygiene education, and snail control. The WHO strategy for schistosomiasis control focuses on reducing disease through periodic, targeted treatment with praziquantel through the large-scale treatment (preventive chemotherapy) of affected populations. 31-10-2020 45

46. Paragonimiasis Paragonimiasis is an infection with parasitic worms. Paragonimiasis can cause illness resembling pneumonia or stomach flu. The infection can last for years. 31-10-2020 46

47. Epidemiology An estimated 293 million people are at risk of paragonimiasis worldwide and it has been reported that about 23 million people in 48 countries are infected. In India, human pulmonary paragonimiasis is emerging as an important public health disease in north-eastern (NE) region. 31-10-2020 47

48. Causes Paragonimiasis is caused by infection with a flatworm, also called a fluke or lung fluke because it commonly infects the lungs. Usually, infection comes after eating undercooked crab or crayfish that carry immature flukes. 31-10-2020 48

49. Pathophysiology Once swallowed by a person, the worms mature and grow inside the body. Over months, the worms spread through the intestines and abdomen. They penetrate the diaphragm muscle to enter the lungs. Once inside the lungs, the worms lay eggs and can survive for years, causing chronic paragonimiasis. 31-10-2020 49

50. Symptoms Gastro-intestinal symptoms- Fever and malaise Diarrhoea Abdominal pain Nausea and vomiting Itching and hives 31-10-2020 50

51. Respiratory symptoms- Cough Shortness of breath Chest pain (made worse by deep breathing or coughing) Haemoptysis Neurological symptoms- Headache Fever Vomiting Double vision Seizures 31-10-2020 51

52. Medical management Praziquantel Triclabendazole Anti-seizure medications (for brain involvement) 31-10-2020 52

53. Cerebral malaria- Severe falciparum malaria Caused by Plasmodium falciparum and may result in an acute encephalopathy (with febrile and acute seizures), which may be fatal or lead to polymorphic neurological sequelae. Caused if parasite-filled blood cells block small blood vessels to brain and swelling of brain or brain damage may occur. Cerebral malaria may cause seizures and coma. 31-10-2020 53

54. Epidemiology According to the World Malaria Report 2017, in the year 2016, more than half of the population (698 million) was at risk of malaria. According to the Report, India accounted for 6% of all malaria cases in the world, 6% of the deaths, and 51% of the global P. vivax cases. The Report estimates the total cases in India at 1.31 million (0.94-1.83 million) and deaths at 23990 (1600-46500). 31-10-2020 54

55. Pathophysiology Pathogenesis of cerebral malaria is due to damaged vascular endothelium by parasite sequestration, inflammatory cytokine production and vascular leakage. The basic underlying defect seems to be clogging of the cerebral microcirculation by the parasitized red cells as a result of increased cytoadherent properties due to which the parasites sequester in these deeper blood vessels. 31-10-2020 55

56. Also, rosetting of both healthy and infected red cells further impairs healthy circulation. This results in hypoxia and brain ischemia as depicted by increased lactate and alanine concentrations along with decreased aspartate and adenosine triphosphate levels. The levels of the biomarkers’ histidine-rich protein II, angiopoietin-Tie-2 system and plasma osteoprotegrin serve as diagnostic and prognostic markers. 31-10-2020 56

57. Symptoms Fever and rigors—the malarial paroxysm Anaemia Jaundice Splenomegaly Hepatomegaly Abnormal posturing Nystagmus Conjugate gaze palsy Opisthotonos Seizures Hypoglycemia Metabolic acidosis Coma 31-10-2020 57

58. Medical management IV artesunate IV quinine dihydrochloride or quinidine gluconate + doxycycline, tetracycline, or clindamycin 31-10-2020 58

59. Toxocariasis Toxocariasis is an illness of humans caused by larvae (immature worms) of either the dog roundworm ( Toxocara canis ), the cat roundworm ( Toxocara cati ) or the fox roundworm ( Toxocara canis ). 31-10-2020 59

60. Toxocariasis is often called visceral larva migrans (VLM). The soil of parks and playgrounds is commonly contaminated with the eggs of T canis , and infection may cause human disease that involves the liver, heart, lung, muscle, eye, and brain. 31-10-2020 60

61. Epidemiology In India, about 39,157 cases of Toxocara infection are reported in humans each year. Almost 15% of the India population is infected with Toxocara , a parasite of dogs and cats that can be passed from animals to humans. 31-10-2020 61

62. Pathophysiology Transmission of Toxocara to humans is usually through ingestion of infective eggs. Eating undercooked rabbit, chicken, or sheep can lead to infection; encysted larvae in the meat can become reactivated and migrate through a human host, causing toxocariasis. 31-10-2020 62

63. There are three main syndromes associated with toxocariasis: • Visceral larva migrans , which encompasses diseases associated with major organs • Covert toxocariasis , which is a milder version • Ocular larva migrans , in which the pathological effects on the host are restricted to the eye and the optic nerve. CNS infestation is rare, but these patients may present with seizures, eosinophilic meningitis, optic neuritis and meningomyelitis. 31-10-2020 63

64. Symptoms Visceral larva migrans – Pallor Fatigue Weight loss Anorexia Fever Headache Skin rash Cough Asthma Chest tightness Increased irritability Abdominal pain Nausea and vomiting 31-10-2020 64

65. Covert toxocariasis – Coughing Fever Abdominal pain Headaches Changes in behaviour and ability to sleep Wheezing Hepatomegaly Lymphadenitis 31-10-2020 65

66. Ocular larva migrans – Loss of vision Red eye White pupil Fixed pupil Retinal fibrosis Retinal detachment Inflammation of the eye tissues, retinal granulomas, and strabismus Toxocara damage in the eye is permanent and can result in blindness 31-10-2020 66

67. Medical management Asymptomatic patients and patients with mild symptoms do not require anthelminthic therapy because infection is usually self-limited. For patients with moderate to severe symptoms, mebendazole 100 to 200 mg po bid for 5 days or albendazole 400 mg po bid for 5 days is often used. 31-10-2020 67

68. Onchocerciasis Onchocerciasis, also known as river blindness, is a disease caused by infection with the parasitic worm Onchocerca volvulus. It is the second-most common cause of blindness due to infection, after trachoma. 31-10-2020 68

69. Epidemiology About 21 million people were infected with this parasite in 2017; about 1.2 million of those had vision loss. As of 2017, about 99% of onchocerciasis cases occurred in Africa. It is currently relatively common in 31 African countries, Yemen, and isolated regions of South America. Over 85 million people live in endemic areas, and half of these reside in Nigeria. Another 120 million people are at risk for contracting the disease. 31-10-2020 69

70. Pathophysiology The parasite worm is spread by the bites of a black fly of the Simulium type. Usually, many bites are required before infection occurs. These flies live near rivers, hence the common name of the disease. Once inside a person, the worms create larvae that make their way out to the skin, where they can infect the next black fly that bites the person. The severity of illness is directly proportional to the number of infected microfilariae and the power of the resultant inflammatory response. 31-10-2020 70

71. Symptoms Severe itching Bumps under the skin Blindness Nodding syndrome- an epileptic encephalopathy characterized by nodding of the head, affecting mainly children in Africa. 31-10-2020 71

72. Mazzotti reaction- Complex symptom seen in patients after undergoing treatment of onchocerciasis with the medication diethylcarbamazine (DEC). Mazzotti reactions can be life-threatening, and are characterized by fever, urticaria, swollen and tender lymph nodes, tachycardia, hypotension, arthralgias, oedema, and abdominal pain that occur within seven days of treatment of microfilariasis . 31-10-2020 72

73. Medical management Ivermectin Doxycycline 31-10-2020 73

74. American trypanosomiasis (Chagas disease) Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi (T. cruzi ). 31-10-2020 74

75. Epidemiology About 6 million to 7 million people worldwide, mostly in Latin America, are estimated to be infected with Trypanosoma cruzi , the parasite that causes Chagas disease. 31-10-2020 75

76. Pathophysiology The main route of transmission (vector-borne transmission) has occurred in Latin America through the insect called triatomine bug, which can carry the Trypanosoma cruzi . Other routes of transmission include: oral (food-borne) transmission, blood/blood products transfusion, mother-to-child (congenital) and organ transplantation transmissions or even laboratory accident transmission. 31-10-2020 76

77. Normally they hide during the day and become active at night when they feed on mammalian blood, including human blood. They usually bite an exposed area of skin such as the face (hence its common name ‘ kissing bug’), and the bug defecates or urinates close to the bite. The parasites enter the body when the person instinctively smears the bug faeces or urine into the bite, the eyes, the mouth, or into any skin break. 31-10-2020 77

78. Symptoms Initial acute phase - 2 months. During the acute phase, a high number of parasites circulate in the blood but in most cases, symptoms are absent or mild and unspecific. In less than 50% of people bitten by a triatomine bug, characteristic first visible signs can be a skin lesion or a purplish swelling of the lids of one eye. Additionally, they can present fever, headache, enlarged lymph glands, pallor, muscle pain, difficulty in breathing, swelling, and abdominal or chest pain. 31-10-2020 78

79. During the chronic phase , the parasites are hidden mainly in the heart and digestive muscles. Up to 30% of patients suffer from cardiac disorders and up to 10% suffer from digestive (typically enlargement of the oesophagus or colon), neurological or mixed alterations. In later years the infection can lead to sudden death due to cardiac arrhythmias or progressive heart failure caused by the destruction of the heart muscle and its nervous system. 31-10-2020 79

80. Medical management Benznidazole Nifurtimox Both medicines are nearly 100% effective in curing the disease if given soon after infection at the onset of the acute phase including the cases of congenital transmission. The efficacy of both diminishes, however, the longer a person has been infected and the adverse reactions are more frequent at older age. 31-10-2020 80

81. Prevention Vector control Blood screening- to prevent infection through transfusion and organ transplantation. Detection and treatment of girls and women of child-bearing with infection is essential, together with the screening of new- born’s and siblings of infected mothers without previous antiparasitic treatment. 31-10-2020 81

82. Spraying of houses and surrounding areas with residual insecticides. House improvements and house cleanliness to prevent vector infestation. Personal preventive measures such as bed nets. Good hygiene practices in food preparation, transportation, storage and consumption. Testing of organ, tissue or cell donors and receivers. 31-10-2020 82

83. Human African trypanosomiasis (sleeping sickness) African Trypanosomiasis, also known as “sleeping sickness”, is caused by microscopic parasites of the species Trypanosoma brucei. 31-10-2020 83

84. Epidemiology Sustained control efforts have reduced the number of new cases. In 2009 the number reported dropped below 10,000 for the first time in 50 years, and in 2018 there were 977 cases recorded. (Africa) 31-10-2020 84

85. Pathophysiology It is transmitted by the tsetse fly ( Glossina species), which is found only in sub-Saharan Africa. Two morphologically indistinguishable subspecies of the parasite cause distinct disease patterns in humans: T. b. gambiense causes a slowly progressing African trypanosomiasis in western and central Africa and T. b. rhodesiense causes a more acute African trypanosomiasis in eastern and southern Africa. 31-10-2020 85

86. Infection and symptoms The disease is mostly transmitted through the bite of an infected tsetse fly but there are other ways in which people are infected: Mother-to-child infection Mechanical transmission through other blood-sucking insects is possible, however, it is difficult to assess its epidemiological impact. Accidental infections in laboratories due to pricks with contaminated needles. Transmission of the parasite through sexual contact. 31-10-2020 86

87. First stage- the trypanosomes multiply in subcutaneous tissues, blood and lymph. This is also called haemo -lymphatic stage, which entails bouts of fever, headaches, enlarged lymph nodes, joint pains and itching. Second stage- the parasites cross the blood-brain barrier to infect the central nervous system. This is known as the neurological or meningo -encephalic stage. In general, this is when more obvious signs and symptoms of the disease appear: changes of behaviour , confusion, sensory disturbances and poor coordination. Disturbance of the sleep cycle, which gives the disease its name, is an important feature. Without treatment, sleeping sickness is considered fatal. 31-10-2020 87

88. Medical management Drugs used in the treatment of first stage: • Pentamidine • Suramin Drugs used in the treatment of second stage: • Melarsoprol • Eflornithine • Nifurtimox Drugs used in the treatment of both stages: • Fexinidazole 31-10-2020 88

89. Angiostrongyliasis Also known as the rat lungworm, is a parasitic nematode (worm) that is transmitted between rats and mollusks (such as slugs or snails) in its natural life cycle. Other animals that become infected such as freshwater shrimp, land crabs, frogs, and planarians of the genus Platydemus , are transport hosts that are not required for reproduction of the parasite but might be able to transmit infection to humans if eaten raw or undercooked. Humans are accidental hosts who do not transmit infection to others. 31-10-2020 89

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91. Epidemiology Angiostrongylus cantonensis occurs widely in the tropics. Most infections occur in Southeast Asia, but small epidemics have been reported more recently from the Caribbean and elsewhere. 31-10-2020 91

92. Transmission Transmission occurs by ingestion of third-stage larvae in raw or undercooked snails or slugs. It can also result from ingestion of raw or undercooked transport hosts such as freshwater shrimp or prawns, crabs and frogs. Nature of the disease Ingested larvae can migrate to the central nervous system and cause eosinophilic meningitis. 31-10-2020 92

93. Symptoms Headache Nausea and vomiting Neck stiffness Fever 31-10-2020 93

94. Medical management Corticosteroids and symptomatic treatment only Prevention Food and water hygiene; in particular avoid eating raw/undercooked snails and slugs, or raw produce such as lettuce can prevent the disease. No vaccine is available. 31-10-2020 94

95. DIAGNOSTIC EVALUATION FOR PARASITIC DISEASES A faecal (stool) exam, also called an ova and parasite test (O&P) This test is used to find ova (eggs) or parasites that cause diarrhoea , loose or watery stools, cramping, flatulence (gas) and other abdominal illness. CDC recommends that three or more stool samples, collected on separate days, be examined. Instruct the patient to put his stool specimens into special containers with preservative fluid. Specimens not collected in a preservative fluid should be refrigerated, but not frozen, until delivered to the lab or the health care provider’s office. 31-10-2020 95

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97. Endoscopy/Colonoscopy Used to find parasites that cause diarrhea, loose or watery stools, cramping, flatulence (gas) and other abdominal illness. Used when stool exams do not reveal the cause of diarrhea. This test looks for the parasite or other abnormalities that may be causing signs and symptoms. 31-10-2020 97

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99. Blood tests Serology - To look for antibodies or for parasite antigens Blood smear- To look for parasites. By looking at a blood smear under a microscope, parasitic diseases such as filariasis, malaria, or babesiosis, can be diagnosed. 31-10-2020 99

100. X-ray, Magnetic Resonance Imaging (MRI) scan, Computerized Axial Tomography scan (CAT) are used to look for some parasitic diseases that may cause lesions in the organs. 31-10-2020 100

101. NURSING MANAGEMENT Nursing care focuses on ongoing assessment of the neurologic status, administering medications, assessing the response to treatment, and providing supportive care. Ongoing neurologic assessment alerts the nurse to changes in ICP, which may indicate a need for more aggressive intervention. The nurse also assesses and documents the responses to medications. 31-10-2020 101

102. Blood laboratory test results, specifically blood glucose and serum potassium levels, need to be closely monitored when corticosteroids are prescribed. Patient safety is also a key nursing responsibility. Injury may result from decreased level of consciousness and falls related to motor weakness or seizures. The nurse must assess the family’s ability to express their distress at the patient’s condition, cope with the patient’s illness and deficits, and obtain support. 31-10-2020 102

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104. Tobias Brummaier et al in 2019 reported a case of blind passenger: a rare case of documented seroconversion in an Angiostrongylus cantonensis induced eosinophilic meningitis in a traveller visiting friends and relatives. A 33-year old woman with a travel history to rural north-eastern Thailand presented to an emergency department in Switzerland with severe headache and vomiting. Eosinophilic meningitis was confirmed as the cause of the symptoms; however, serologic investigations failed to confirm an A. cantonensis infection on the first evaluation. Nevertheless, empirical treatment with an anthelminthic and steroid regimen led to a rapid alleviation of symptoms. Repeated serology confirmed seroconversion 2 weeks after treatment initiation. Parasitic etiology must be considered in returning travellers who present with symptoms compatible with a central nervous system infection. A thorough medical history, including types of food consumed, is paramount and can often suggest differential diagnosis. Neuroangiostrongyliasis is rare and might be missed if serology does not cover possible seroconversion. 31-10-2020 104

105. CONCLUSION Parasitic diseases of the central nervous system are associated with high mortality and morbidity, especially in resource-limited settings. The burden of these diseases is amplified as survivors are often left with neurologic sequelae affecting mobility, sensory organs, and cognitive functions, as well as seizures/epilepsy. The complexity of parasitic life cycles and geographic specificities, as well as overlapping clinical manifestations in the host reflecting the diverse pathogenesis of parasites, can present diagnostic challenges. Hence an overview of these parasitic diseases clinical aspects, diagnosis, therapeutic strategies and recent milestones, and aspects related to prevention and control were discussed. 31-10-2020 105

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