Vector-Borne Diseases of Interest in Ontario

Transcription

1 Vector-Borne Diseases of Interest in Ontario

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3 Ontario s Vector-Borne Diseases Reportable vector-borne diseases in Ontario are: West Nile Virus (WNV) Lyme disease (LD) Eastern Equine Encephalitis (reported under encephalitis) Malaria Yellow Fever Dengue (reported under hemorrhagic fever)

4 Vector-Borne Disease Program Ontario s program consists of the following: Human surveillance Vector surveillance Vector control Public education

5 Roles of Public Health Units To conduct vector surveillance in an effort to assess the risk of vector-borne diseases to humans. To conduct local risk assessments based on surveillance data and local ecological factors. Create local programs based on the results of the risk assessments.

6 EZVBD Unit Activities Coordinate the provincial program Provide expert consultation, create guidelines, best practices, and data analysis To ensure that health units are able to conduct local risk assessments properly

7 Mosquito Life Cycle 7

8 Objectives of Mosquito Surveillance To determine the location and infection rate of mosquito vectors. Mosquito surveillance is one of the most effective tools in assessing the risk of mosquito-borne diseases to the public. Mosquito surveillance is conducted by all health units in Ontario. This surveillance also gives Ontario the opportunity to monitor for invasive species and other mosquito-borne diseases such as Eastern Equine Encephalitis

9 How Mosquito Surveillance is Conducted Health units set up mosquito traps on a weekly basis. The traps are set in the same place from year to year. Each health unit is allotted a certain number of traps per week depending on risk, geographical size and population. Trapped mosquitoes are sent to qualified service providers for speciation and viral testing The service providers report the data to the health units and ministry on a weekly basis EZVBDU staff create a weekly vector surveillance report that is distributed to the health units

10 Mosquito Surveillance (Trapping) CDC Miniature Light Trap Attracts host-seeking adult mosquitoes. Larval Dipping Looking for larvae in their aquatic habitat.

11 Mosquito Control in Ontario There are three larvicides currently approved for WNV control in Ontario: 1. Bacillus thuringiensis israelensis (Bti) 2. Bacillus sphaericus (B. sphaericus) 3. Methoprene The only adulticide product currently approved for use in Ontario is malathion.

12 Malaria CDC/ James D. Gathany 12

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14 Malaria In 2010, malaria caused about 219 million cases (with an uncertainty range of million) and an estimated deaths (with an uncertainty range of to ), mostly among African children. Malaria mortality rates have fallen by more than 25% globally since 2000, and by 33% in the WHO African Region. The Democratic Republic of the Congo and Nigeria account for over 40% of the estimated total of malaria deaths globally There are four parasite species that cause malaria in humans: Plasmodium falciparum, P. vivax, P. malariae, P. ovale P. falciparum and P. vivax are the most common P. falciparum is the most deadly. 14

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18 Symptoms Can take from one week to several months to occur (depending on the type of malaria parasite). Are often flu-like, including: fever, sweats, chills, headache, abdominal pain, muscle and joint pain, nausea and vomiting, diarrhea and feeling generally unwell. In more severe cases may include seizures, coma, kidney and respiratory failure, and shock which may lead to death. Treatment Specific treatment options depend on the species of malaria, the likelihood of drug resistance (based on where the infection was acquired), the age of the patient, pregnancy status, and the severity of infection. 18

19 Exposure region* Exposure regions for imported malaria cases in Ontario, Canada ( ) Malaria cases ( ) P. falciparum P. vivax P. ovale P. malariae Plasmodium sp. Total (%) Africa (66.0) Asia (27.1) Americas (5.4) Oceania (<1) Europe (<1) Australia (<1) Total (100) Nelder et al

20 Imported malaria distribution and case rate in Ontario s boards of health ( ) 20

21 DENGUE Aedes aegypti Aedes albopictus CDC/James Gathany 21

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23 Vector Borne Zoonotic Dis. 2007; 7(1):

24 Dengue Flavivuris: similar to Yellow Fever, WNV, St. Louis Encephalitis 40% of world s population at risk of dengue with ~ million infection every year Four different serotypes with lifelong immunity after recovery Subsequent infection with another serotype increases the risk of severe dengue (i.e. dengue hemorrhagic fever) DHF is the leading cause of hospitalization and death in Asian and Latin American children 24

25 Symptoms Severe headache Pain behind the eyes Nausea, Vomiting Swollen glands Muscle and joint pains Rash Severe Dengue Persistent vomiting Rapid breathing Bleeding gums Blood in vomit Fatigue, restlessness The next hours of the critical stage can be lethal; proper medical care is needed to avoid complications and risk of death. 25

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28 Dengue in Florida 2009: Keys (22) 2010: Keys (66), Broward (1), Miami-Dade (1) 2011: Miami-Dade (3), Palm Beach (2), Martin (1), Hillsborough (1) 2012: Miami-Dade (1), Osceloa (1), Seminole (1) 2013: Miami-Dade (1), Martin (22) 28

29 CHIKUNGUNYA Aedes aegypti Aedes albopictus CDC/James Gathany 29

30 Chikungunya Alphavirus from the Togaviridae family Transmitted by Aedes mosquitoes to vertebrates. The word chikungunya comes from the Makonde dialect in Tanzania, and means 'which bends up', related to the posture of the suffering patients 30

31 Symptoms Fever Joint pain Headache Muscle pain Rash Joint swelling Treatment Supportive care Pain releavers- 31

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36 WEST NILE VIRUS 36

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38 Culex pipiens -The primary vector for WNV in Ontario

39 The approximate global distribution of West Nile virus, by country, state, and province. 39 Modified from: Gubler D J Clin Infect Dis. 2007;45:

40 Culex pipiens

41 CDC Miniature Light Trap Attracts host-seeking mosquitoes Uses light and CO 2 (Dry Ice) as bait Mosquitoes are sucked into the trap via a fan

42 WNV Activity in Ontario Source: Ontario Ministry of Health and Long-Term Care, integrated Public Health Information System (iphis) database, extracted by Public Health Ontario [2013/11/27].

43 Count Acc. Degree Days Mosquito Seasonality and Human Cases 40 Overwintering 2 nd Generation 3 rd Generation Overwintering May June July Aug Sept Oct Week Code Avg. Human Estimated Exposure Avg. Human Onset Avg. Human Reported Ave. # Positive Mosquito Pools Percent Positive Mosquitoes Acc. Degree-days 0 43

44 Source: Ontario Ministry of Health and Long-Term Care, integrated Public Health Information System (iphis) database, extracted by Public Health Ontario [2012/10/09].

45 Location of West Nile Virus positive mosquito pools in Ontario,

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48 Clinical Manifestations of WNV Non- Neurological Syndrome Abrupt onset of fever Headache Sudden sensitivity to light Myalgia Weakness Abdominal pain Maculopapular rash (often transient)

49 Gorsche, R. et al. CMAJ 2005;172:1440

50 Outcome of WNV Non-Neurological Syndrome Acute phase of illness lasts several days Fatigue and weakness can last for weeks

51 Clinical Manifestations of WNV Neurological Syndrome Neck stiffness Headache typical of aseptic meningitis Mental status changes indicating encephalitis (i.e. confusion) Movement disorders (i.e. tremors, Parkinsonism) Seizures Acute flaccid paralysis

52 WNV Human Infection Iceberg 1 CNS disease case = ~150 total infections <1% CNS disease ~20% West Nile Fever ~10% fatal (<0.1% of total infections) Very crude estimates ~80% Asymptomatic 52

53 Treatment of WNV Treatment of WNV is supportive No specific therapy has been proven effective Control research trials with interferon, Immune Globulin with WNV-specific antibodies and RNA translation inhibitors is underway

54 EASTERN EQUINE ENCEPHALITIS 54

55 EEE Activity YEAR EEE Positive Mosquito Pools EEE Horses no data no data * ^ *First Nations (Wahta): 10 pools Culiseta melanura and 2 pools Aedes vexans. ^Health Unit (NPS) 1 pool and First Nations (Wahta) 2 pools all Culiseta melanura.

56 Easter Equine Encephalitis Activity

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58 Total number of human EEE cases reported to the CDC in the United States between 1964 and

59 news.bbc.co.uk/.../medical_notes/ stm 59

60 Ticks & Lyme disease in Ontario Curtis Russell Program Consultant

61 Lyme disease History In 1991 only one population of ticks that carry Lyme disease (LD) was known in Canada located in Ontario at Long Point Provincial Park. After that the following areas were identified: Turkey Point Provincial Park Rondeau Provincial Park Point Pelee National Park Prince Edward Point National Wildlife Area In 2006 the Ministry participated in tick surveillance studies with the Public Health Agency of Canada and discovered an new endemic area in St. Lawrence Islands National Park area The Ministry started to active tick surveillance in 2007.

62 Ticks in North America

63 Blacklegged Tick (BLT) American Dog Tick R. Lindsay PHAC

64 Count Count Blacklegged Tick Month American Dog Tick Month

65 The blacklegged tick (Ixodes scapularis) is the vector responsible for transmitting Lyme disease (LD) in Ontario R. Lindsay PHAC

66 Swanson et al. CLINICAL MICROBIOLOGY REVIEWS, Oct. 2006, p

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68 Tick Habitat

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71 NYMPH TICK ENGORGEMENT ADULT IDSA Guidelines 71

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73 Adult Tick Abundant October to May Adult Tick Abundant October to May Nymphal Tick Abundant May to Late July Larval Tick Abundant August to October

74 Tick Populations Established Blacklegged ticks found in the same area over multiple years Endemic Blacklegged ticks found in the same area over multiple years Blacklegged ticks not positive for Borrelia burgdorferi Blacklegged ticks and small mammals found positive for Borrelia burgdorferi

75 Photograph courtesy of Dr. Thomas Nicholls

76 North America Bird Flyways

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78 Risk maps for possible establishment of BLTs Up to 2019 N. Ogden PHAC

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80 N. Ogden PHAC

81 2080+ N. Ogden PHAC

82 Lyme Disease Surveillance in Ontario Passive Surveillance Ticks are submitted to the health unit Physicians, veterinarians, public Active Surveillance Go out into the environment to look for the ticks Tick dragging Small mammal trapping

83 Objectives of Tick Surveillance Establish presence/geographic distribution of LD vector. Adventitious ticks vs. established populations. Size/density of vector populations. Prevalence of B. burgdorferi infection. Infer risk of exposure based on the above factors and intensity of human use of habitat/opportunity for exposure to infected vectors. Implement measures to mitigate risk of exposure & subsequent infection and disease.

84 Drag Sampling

85 Small Mammal Trapping

86 Number of Ticks Submitted PHOL Tick Submissions Year I. scapularis Other tick species Scientific Name Common Name Total Percent Ixodes scapularis Blacklegged Tick Dermacentor variabilis American Dog Tick Ixodes species Ixodes cook ei Woodchuck Tick Amblyomma americanum Lone Star Tick Ixodes marxi Squirrel Tick Amblyomma cajennense Cayenne Tick Rhipicephalus sanguineus Brown Dog Tick Ixodes muris Mouse Tick Amblyomma species Dermacentor albipictus Winter Tick Dermacentor species Ixodes pacificus Western Blacklegged Tick

87 Grand Total Ixodes scapularis Dermacentor variabilis Ixodes species Amblyomma americanum Amblyomma cajennense Amblyomma species Dermacentor albipictus Dermacentor species Ixodes cookei Ixodes marxi Ixodes muris Ixodes pacificus Rhipicephalus sanguineus Ticks submitted to PHOL by location of submitters HU of residence HU LGL KFL NIA EOH OTT HDN WEC HPE HAM TOR LAM HKP HAL BRN WAT DUR SMD YRK MSL CHK PEE PTC THB REN OXF ELG GBO NWR WDG PDH ALG NPS SUD HUR TSK PQP (blank) Grand Total

88 Percentage B. burgdorferi-positivity and total I. scapularis by submitter town of exposure ( ). 88 Data source: PHAC, extracted [2014/03/12]

89 Number of cases Rate per 100,000 population Number of reported confirmed and probable human Lyme Disease cases and rate (per 100,000 population) by year, Ontario, 2002 to * Probable Confirmed Overall rate Data Source: Ontario Ministry of Health and Long-Term Care, integrated Public Health Information System (iphis) database, extracted by Public Health Ontario [2014/02/04] Population estimates (for rate calculations): Ontario Ministry of Health and Long-term Care, IntelliHEALTH Ontario, extracted by Public Health Ontario [2013/09/16]. Notes: Population estimates for 2012 were used to estimate provincial population counts for 2013 Data from 2009 onwards includes both confirmed and probable cases. The Lyme Disease confirmed case definition changed in 2009 such that clinical cases were no longer considered confirmed. Clinical cases are now considered probable cases and case counts for 2009 and subsequent years include both confirmed and probable cases to ensure valid comparisons of trends over time. 89

90 Human Lyme disease cases based on location of likely exposure, by municipality, Data source: Ontario Ministry of Health and Long-Term Care, integrated Public Health Information System (iphis) database, 90 extracted by Public Health Ontario [2014/02/19].

91 Municipalities identified as the most likely exposure location for locally acquired Lyme disease cases: Ontario, 2013 Data source: Ontario Ministry of Health and Long-Term Care, integrated Public Health Information System (iphis) database, 91 extracted by Public Health Ontario [2014/02/19].

92 New Areas of Concern Based on surveillance conducted by PHO and PHAC, the Rainy River area in Northwestern Health Unit has a confirmed endemic location. Low levels of anaplasma and babesia were also present in the ticks. In May, PHO and Lambton Health Unit conducted active tick surveillance at the Pinery Provincial Park and found blacklegged ticks. This indicates that this is a new risk area. 92

93 Personal Protection Wear white, clothing (pants and shirt, or coveralls, and socks) so that ticks can be easily seen Pants should be tucked into socks and/or boots Wear repellents with DEET Do a complete check of clothing (and the drag cloths) when finished sampling at each locality (i.e., in the field)

94 Personal Protection continued At home, carefully recheck your clothing and boots; and thoroughly check your skin for attached ticks Use the Buddy system Bite sites should be monitored and any attached ticks should be preserved (frozen) for identification and possible testing should symptoms develop It is important to remember that attached ticks do not immediately start to transmit the agent of LD but rather it takes 24 to 48 hours of attachment before the bacteria is transferred

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98 From: IDSA Guidelines CID 2006:43 (1 November)

99 Lyme disease clinical syndrome

100 Lyme Neuroborreliosis: Difference in Manifestation Clinical Features N. American LNB European LNB Causative species B. burgdorferi s.s B. garnii or B. afzelli LNB as a percentage of all Lyme cases Low High* LNB as presenting manifestation of infection Rare Common* Multiple EM lesions Common Rare Painful radiculitis Rare Common Skin manifestation (ACA or lymphocytoma) Never Not rare Lyme arthritis Common Unusual Intrathecal antibody production Not prominent Prominent *Mostly B. garnii LNB: Lyme neuroborreliosis ACA: acrodermatitis chronica atrophicans Pachner et al Ann Neurol, 56(3)

101 Laboratory Tests for Lyme disease Serologic testing Serum IgM ELISA Peaks at 3 6 weeks after onset of infection Serum IgG ELISA Usually increases slowly and is highest weeks to months later Western Blot testing Done on all ELISA positive samples for confirmation

102 Performance characteristics of each assay in patients with Lyme disease Test EM, acute EM, convalescent phase* % Reactivity in patients with Neurological involvement Arthritis Whole-cell ELISA (IgG only) 100 (IgG only) IgM IgG Two-tier testing * Sera obtained after abx treatment Aguero-Rosenfeld et al, 2005 Clin Micro Rev

103 Challenges posed by private laboratories in USA Private labs uses variety of different assays to diagnose Lyme disease None of them are scientifically validated In 2005 the CDC placed a notice in their Morbidity and Mortality Weekly Report (MMWR) cautioning about using these private laboratories: 103

104 Number of Lyme disease tests done at OAHPP-PHL in Samples Tested for EIA

105 Post Lyme Disease Treatment Syndrome (PLDS) Often called chronic Lyme disease, this condition is properly known as Post-treatment Lyme disease Syndrome (PTLDS) Can be divided into 2 groups: sero-positive or sero-negative group Some evidence that show that delay in treatment of Lyme disease may result in longer PLDTS The exact cause of PTLDS is not yet known. Most medical experts believe that lingering symptoms are due to residual damage to the tissues and the immune system that occurred during the infection. Similar complications and auto-immune responses are known to occur following other infectious diseases. CDC There is no credible scientific evidence that PTLDS is caused by persistent infection. CDC 105

106 Long-Term Antibiotic Treatment The National Institute of Allergy and Infectious Diseases (NIAID) has funded three placebo-controlled clinical trials on the efficacy of prolonged antibiotic therapy for treating PLDS. Carefully designed, placebo-controlled studies have failed to demonstrate that prolonged antibiotic therapy is beneficial. NIAID Pages/chronic.aspx 106

107 Questions? 107