Notea on 2. VIRAL VECTOR BORNE DISEASE.pptx

Contains detailed notes on viral vector borne diseases

1. Assignment. Read and make notes Schistosomiasis Two organisisms Schistosoma hematobium Schistosoma Japonicum Definition Epidemiology Mode of transmission Life cycle Predisposing factors & causes Sign/Symptoms & Complications Management Prevention and control

2. DENGUE & DENGUE HEMORRHAGIC FEVER YELLOW FEVER ZIKA VIRUS CHIKUNGUNYA VIRUS VIRAL VBDS

3. DENGUE & DENGUE HEMORRHAGIC FEVER YELLOW FEVER VIRAL VBDS

4. DENGUE FEVER AND DENGUE HEMORRHAGIC FEVER

5. 5 Definition Epidemiology Mode of transmission Life cycle Predisposing factors & causes Sign/Symptoms & Complications Management Prevention and control Objectives

6. Definition of Dengue Fever 6 Dengue fever is a n acute vector borne disease caused by Dengue viruses (categorized into types 1,2,3,4) Transmitted by the vectors: Aedes aegypti in Kenya Aedes albopictus : is very common in Hong Kong.

7. 7 About 50 million cases annually worldwide Incidence of dengue fever highest in tropical and subtropical regions Recent increase in disease activity worldwide. As at 9 th July 2014, the number of cases in England for instance, has risen by 60% from 2012 to 2013 because of most travelers coming back from holidays from India and Thailand. Epidemiology

8. 6/8/2020 Prepared by Sammy Barasa; BSN, MPH (Epidem.) 8 Regions with dengue fever Dengue Fever 2001

9. The Situation in K enya The first dengue outbreak in Kenya was reported in 1982 in the coastal region. In 2011, more than 5,000 cases were reported in an outbreak in Mandera , Kenya-Ethiopia Border. In 2013: over 300 cases in a “small” outbreak in Mandera ; this prompted the Gov. to institute prompt disease surveillance and mitigation of the spread. In 2013-2014- subsequently in Mombasa city in the coastal region. Currently an outbreak is on going at the cost (May 2020) 9

10. Vector Aedes aegypti 6/8/2020 10 Aedes aegypti : found throughout tropical & subtropical regions of America, Africa and Asia, as well as southeastern US, Indian Ocean Islands & northern Australia.

11. 12 Aedes aegypti  prefers to lay its eggs in artificial water containers, to live in close proximity to humans, and to feed on people rather than other vertebrates. Vector Cont’d

12. Mode of Transmission 13 Dengue virus is primarily transmitted by  Aedes  mosquitoes, particularly  A. aegypti A healthy person gets the disease when he is bitten by an infected mosquito. The virus enters his blood from the mosquito’s saliva. An infected person could transmit the virus to mosquitoes if he is bitten by a mosquito anytime from the onset to the reduction of the fever (a period of about 6 to 7 days). The disease is then spread by mosquitoes. N/B : Dengue fever is not spread by contact with infected persons .

13. 14 Humans are the primary host of the virus but it also circulates in nonhuman primates. Mode of Transmission Cont’d

14. 15 OTHER MODES OF TRANSMISSION Via infected blood products Organ donation. Vertical transmission  MTCT. Mode of Transmission Cont’d

15. Transmission 16 Infected person Healthy person Infected mosquito Incubation Period: 3 to 14 days Most commonly 4 to 7 days

16. Replication and Transmission of Dengue Virus (Part 1) 1. Virus transmitted to human in mosquito saliva 2 . Virus replicates in target organs 3. Virus infects white blood cells and lymphatic tissues 4. Virus released and circulates in blood 3 4 1 2

17. Replication and Transmission of Dengue Virus (Part 2) 5. Second mosquito ingests virus with blood 6. Virus replicates in mosquito midgut and other organs, infects salivary glands 7. Virus replicates in salivary glands 6 7 5

18. 19 Types 1. Classical dengue 2. Dengue haemorrhagic Fever (DHF)

19. Clinical features of Classical Dengue. 20 Fever : continuous for 3 to 5 days Severe headache Painful limbs, joint pain, muscle pain, back pain, pain behind eyeballs

20. Symptoms of Classical Dengue 21 R ash appears on the 3 rd to 4 th day after onset. Nausea, vomiting. Slight g um bleeding and nasal bleeding. Extreme fatigue and depression may follow recovery. In very rare cases, the condition may worsen into dengue hemorrhagic fever, lead ing to hemorrhage, shock or even death.

21. The more severe form of Dengue is Dengue Hemorrhagic Fever ( dhf ) 22 http://woodshedenvironment.wordpress.com/2010/12/29/dengue-fever-is-dangerous-slideshow-v-1-3-is-here/

22. Clinical Features of Dengue Hemorrhagic Fever 23 Deadly! Severe and continuous pain in abdomen; Bleeding from the nose, mouth and gums or skin bruising; frequent vomiting with or without blood; stools, like coal tar. After several days the patient becomes irritable, restless, and sweaty.

23. Dengue Hemorrhagic fever causes death through dysfunction of endothelium and disordered blood clotting. 24

24. Treatment 25 At present, there is no drug that can treat dengue fever effectively. Patients infected with classical dengue usually recovers in 1 to 2 weeks .

25. Treatment Cont’d 26 For serious cases, supportive treatments: i.e. administer antipyretics such as acetaminophen BUT NOT Aspirin, because it can worsen the bleeding.

26. Prevention: Protect Yourself against Dengue Fever 27 There is no vaccine available against dengue , and there are no specific medications to treat a dengue infection. This makes prevention the most important step, and prevention means avoiding mosquito bites, advise those who live in or travel to an endemic area

27. Control the Spread of Dengue Fever 28 Prevent the patient from being bitten by mosquitoes.

28. Prevention of Mosquito Bites 29 Avoid going out in the hours when Aedes mosquitoes feed or wear light- coloured , long-sleeved clothing and trousers.

29. Prevention Cont’d 30 Apply DEET-containing mosquito-repellents over exposed parts of the body and clothes every 4 to 6 hours. For DEET products used by children, its concentration should be less than 10%.

30. Prevention Cont’d 31 Your place of accommodation should have air-conditioners or mosquito nets. Otherwise, hang mosquito screens around your bed, use insecticides o r coil incenses to repel mosquitoes.

31. Prevention Cont’d 32 Install mosquito screens to doors and windows so that mosquitoes can’t get in.

32. Elimination of Mosquitoes 33 The most effective way to eliminate mosquitoes is to keep the environment clean and to remove stagnant water so that mosquitoes can’t breed.

33. Possible Breeding Grounds of Aedes Albopictus 34 Artificial containers: Vases, saucers underneath flower pots, trays underneath air-conditioners, buckets, jars and jugs of earthenware, cement troughs, dumped tyres and solid wastes such as c ans , disposable cups and bowls, and plastic bags.

34. Possible Breeding Grounds of Aedes Albopictus & aegypti 35 1. Natural containers: The hollow space inside a bamboo, hollows of a tree and the rachis of a leaf.

35. Elimination of Mosquitoes 36 2. Artificial containers: Cover water containers tightly so that mosquitoes can’t get in to lay eggs.

36. Elimination of Mosquitoes 37 Dispose of domestic wastes properly to prevent the accumulation of stagnant water. Dispose of empty bottles, cans and lunchboxes properly, such as into a covered bin.

37. Elimination of Mosquitoes 38 Change water for vases and aquatic plants at least once a week, leaving no water under the pots or in the bottom saucers. Scrub the container surfaces thoroughly to prevent mosquito eggs sticking on them.

38. Elimination of Mosquitoes 39 Remove or puncture any dumped tyres to prevent the accumulation of stagnant water.

39. Elimination of Mosquitoes 40 Ditches should be free from blockage.

40. Elimination of Mosquitoes 41 Fill up uneven ground surfaces to prevent the accumulation of stagnant water.

41. Elimination of Mosquitoes 42 Remove stagnant water immediately if mosquitoes are found to be breeding. Use environmentally friendly insecticides such as lavicidal oil if necessary.

42. Elimination of Mosquitoes 43 In cultivation ponds, water tanks or large containers, biological controls such as keeping fishes to eat mosquito larvae would be a good option.

43. Simple message to schools & the community: Let’s remove stagnant water and eliminate mosquitoes 44 Conduct health education on the above preventive measures

44. SNNOOOOOOOOOZEE!!! Haiya those who have been dozing wake up for a quiz! 45

45. YELLOW FEVER

46. Introduction 47 Definition: Is a zoonotic acute tropical viral infectious disease. Epidemiology: Yellow fever is endemic in tropical and subtropical areas of South America and Africa. Worldwide there are about 600 million people living in endemic areas. WHO officially estimates that there are 200,000 cases of disease and 30,000 deaths a year; the number of officially reported cases is far lower. An estimated 90% of the infections occur on the African continent.

47. Introduction Cont’d 48 In 2008, the largest number of recorded cases were in Togo , No Yellow Fever in Tanzania. Yellow Fever spreads very rapidly, and the case fatality rate may reach as high as 30% in non-immune populations.

48. Predisposing factors & causes 49 Caused by an arbovirus called yellow fever virus of the flavivirus . Those at risk are people working in the forest or herders. Populations in endemic areas.

49. Transmission Cycle 50 Yellow fever virus  has three transmission cycles: Sylvatic (Jungle) Inter­mediate (savannah), Urban. 1. The sylvatic (jungle) cycle: involves transmission of the virus between non-human primates (e.g., monkeys) and mosquito species found in the forest canopy. The virus is transmitted by mosquitoes from monkeys to humans when humans are visiting or working in the jungle (occasional yellow fever infections).

50. Transmission Cycle 51 2. In Africa, an intermediate (savannah) cycle exists that involves transmission of virus from mosquitoes to humans living or working in jungle border areas. In this cycle, the virus can be transmitted from monkey to human or from human to human via mosquitoes. 3. The urban cycle involves trans­mission of the virus between humans and urban mosquitoes, primarily Aedes aegypti . The virus is usually brought to the urban setting by a viremic human who was infected in the jungle or savannah.

51. the 3 cycles 6/8/2020 52

52. Signs & Symptoms of Yellow Fever 6/8/2020 53 Many infections are sub-clinical, leading to immunity without definite illness. Often the onset of Yellow Fever is sudden.

53. Signs & Symptoms High fever + Chills Headache & Backache Muscle aches Stage One (3-6 days after exposure) Loss of appetite Nausea + Vomiting Jaundice, due to liver necrosis. 6/8/2020 54

54. Signs, Symptoms & COMPLICATIONS Stage Two: Remission 3-4 days Recovery possible Stage Three: Toxic period Vomiting Bleeding/ Epistaxis & gums Nephritis, Anuria,Kidney & liver failure, Delirium, seizures Heart damage 55 Coma Shock Death NOTE: Beyond 7 days one may survive.

55. Management 56 No cure! Hospitalization is advisable and intensive care may be necessary because of rapid deterioration in some cases. S ymptomatic treatment includes: rehydration and pain relief with drugs like acetaminophen. NOTE: Do not use aspirin; its anticoagulant effect thus can worsen internal bleeding occurring in YF. Nurse pt under an ITN to prevent re-infection. Don’t refer unless otherwise, just Notify.

56. Prevention & control 57 1. Avoid Mosquito Bites: Use insect repellent while outdoors, Wear proper clothing to reduce mosquito bites. Be aware of peak mosquito hours. The peak biting times for many mosquito species is dusk to dawn. However, Aedes aegypti , one of the mosquitoes that transmits yellow fever virus, feeds during the daytime, thus use repellent and protective clothing during daytime as well as during the evening and early morning.

57. Prevention & control 58 2. Vaccination Yellow fever vaccine is recommended for persons aged ≥ 9 months who are traveling to or living in areas at risk for yellow fever virus transmission in South America and Africa.  Yellow fever vaccine may be required for entry into certain countries.

58. 59 Case and outbreak control: In case of a YF case/outbreak, prevent spread by: Isolation in screened areas Inform regional PHO/MOH. Mass immunization campaign Spray the houses of the pt and neighbors with insecticides. Apply larvicides to all possible breeding places of aedes mosquitoes, including small receptacles and axils of certain plants. TASK: What are the differential diagnosis for YF?

59. Zika Virus epidemiology

60. Single stranded RNA virus Genus f lavivirus , family Flaviviridae Closely related to dengue, yellow fever, Japanese encephalitis, and West Nile viruses Primarily transmitted through the bite of an infected Aedes species mosquito ( Ae. aegypti and Ae . albopictus ) Zika Virus (Zika) Aedes aegypti Aedes albopictus

61. Before 2015, Zika outbreaks occurred in Africa, Southeast Asia, and the Pacific Islands. Currently outbreaks are occurring in many countries and territories. No Zika Virus in Kenya according to KEMRI http://www.cdc.gov/zika/geo/index.html

62. Bite from an infected mosquito Maternal-fetal Peri-conceptional Intra-uterine Perinatal Sexual transmission from an infected person to his or her partners Laboratory exposure Transmission

63. Zika may be spread through blood transfusion. Zika virus has been detected in breast milk.  There are no reports of transmission of Zika virus infection through breastfeeding. Based on available evidence, the benefits of breastfeeding outweigh any possible risk.

64. Incubation period for Zika virus disease is 3–14 days. Zika viremia ranges from a few days to 1 week. Some infected pregnant women can have evidence of Zika virus in their blood longer than expected. Virus remains in semen and urine longer than in blood . Incubation and viremia 3 – 14 days

65. Clinical illness is usually mild. Symptoms last several days to a week. Clinical features

66. Many infections are asymptomatic . Most common symptoms Acute onset of fever Maculopapular rash Joint pain Conjunctivitis Other symptoms include muscle pain and headache . Symptoms

67. Diagnosis Antibody Tests Antigen Tests (PCR)

68. Zika virus disease is a nationally notifiable condition. Reporting cases

69. Zika virus infection during pregnancy is a cause of microcephaly and other severe brain and birth defects. Zika and pregnancy outcomes

70. Congenital Zika syndrome is associated with five types of birth defects that are either not seen or occur rarely with other infections during pregnancy: Severe microcephaly (small head size) resulting in a partially collapsed skull Decreased brain tissue with brain damage (as indicated by a specific pattern of calcium deposits) Damage to the back of the eye with a specific pattern of scarring and increased pigment Limited range of joint motion , such as clubfoot Too much muscle tone restricting body movement soon after birth Congenital Zika syndrome

71. Case definition of microcephaly Baby with microcephaly

72. Measuring head circumference for microcephaly http:// www.cdc.gov/zika/pdfs/microcephaly_measuring.pdf Baby with typical head size Baby with Microcephaly Baby with Severe Microcephaly

73. There is no vaccine or medicine for Zika. Treat the symptoms of Zika Rest F luids to prevent dehydration Acetaminophen to reduce fever and pain. Nutrition Preconception advice for mothers or partners exposed to Zika Virus Careful measurement of head circumference post birth Brain ultra sound for newborn post birth Protect from mosquito bites during the first week of illness, when Zika virus can be found in blood. Treatment

74. Chikungunya

75. Chikungunya is a relatively rare form of viral fever. Causative organism : An alphavirus Vector : mosquito bites from the Aedes aegypti mosquito.

76. EPIDEMIOLOGY Common in Asia and Africa. In 2016, there was an outbreak in Kenya, Mandera county. About 260 people tested positive for the virus, but many others went unreported. Many medics also suffered from it. Currently, there is an outbreak in the coastal region 32 cases of Chikungunya fever out of 120 suspected cases confirmed ( 1/2/2018).

77. Aedes aegypti mosquito

78. BREEDING SOURCES

79. HOST MAN The main virus reservoirs are monkeys, but other primates, mammals and birds can also be affected

80. TRANSMISSION This virus is transmitted only by mosquitoes The mosquito picks up the virus from an infected person during the viraemic period – within five days from the day of starting of symptoms An infected mosquito will remain infected all its life span and can transmit the virus each time it bites An infected person cannot spread the infection directly to other persons

81. SYMPTOMS Fever Which Can Reach 39°C. Petechial or Maculopapular rash Usually Involving the Limbs and Trunk Arthralgia or Arthritis Affecting Multiple Joints Which Can Be Debilitating. Headache, Conjunctival Infection and Slight Photophobia.

82. DIAGNOSIS ELISA : Antibody testing Polymerase chain reaction (PCR): Antigen testing

83. COMPLICATIONS Symptoms resolve within 7-10 days R etinitis, myocarditis, hepatitis, nephritis, bullous skin lesions, hemorrhage, meningoencephalitis

84. Treatment There is no active treatment Pain control: Analgesics, Control of pyrexia: antipyretics fluid supplementation Nutrition Rest Support Movement and mild exercise tend to improve stiffness and morning arthralgia Patients should be protected from further mosquito exposure during the first week of illness to reduce the risk of local transmission.

85. Is there any vaccine? No vaccine available Chikungunya confers a life-long immunity on the infected person.

86. PREVENTION Elimination of stagnant water at home, schools and work place to avoid breeding of mosquitoes. Using insect repellents over the exposed parts of the body.   Using mosquito screens or nets in non – Air-conditioned rooms.  Wearing the long sleeved clothes like long trousers of a light shade for protection against mosquitoes.

87. Properly covering all water tanks so that mosquitoes cannot get in Getting rid of any container capable of retaining water in the outdoor surroundings (used tyres , food cans, garbage, saucers under flower pots, etc) Renew water in flower vases at least once a week

88. CONTROL Eliminate other breeding places in and around houses

89. Educate community about the disease, mode of its transmission, availability of treatment and adoption of control measures.