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Arboviral Surveillance
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ARBOVIRAL SURVEILLANCE
Julius L. Tonzel, MPH
Sean Simonson, MPH
Infectious Disease Epidemiology Section
Louisiana Department of Health
Disclosure Statement
• The speakers, the speakers’ spouses, and the planning committee have disclosed no relationship with a commercial interest that would create a conflict of interest with this presentation
Objectives
• Investigate cases for endemic arboviruses
• Investigate cases for imported arboviruses
• Participate in the Zika Pregnancy Registry
Encephalitis
• Confusion, agitation or hallucinations
• Seizures
• Loss of sensation or paralysis in certain areas of the face or body
• Muscle weakness
• Problems with speech or hearing
• Loss of consciousness
Arboviral Surveillance
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Arboviruses Endemic to Louisiana
• West Nile virus
• St. Louis virus
• Eastern Equine virus
• La Crosse virus
• Jamestown Canyon virus
West Nile Encephalitis Virus (WNV)
• Flavivirus
• Maintained by Culex species mosquitoes and wild birds
• Symptoms• Fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, number and paralysis
• ~2500 cases annually
• Introduced to Louisiana in 2001• Most common arboviral disease in US
St. Louis Encephalitis Virus (SLE)
• Flavivirus
• Maintained by Culex species mosquitoes and wild birds
• Symptoms• Fever, headache, neck stiffness, stupor, disorientation, coma, tremors, occasional convulsions and spastic paralysis
• ~7 cases reports annually
Arboviral Surveillance
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Eastern Equine Encephalitis Virus (EEE)
• Alphavirus
• Maintained by Culiseta melanuramosquitoes and birds
• Transmitted by Aedes, Coquillettidia andCulex species
• Symptoms• Fever, headache, irritability, restlessness, drowsiness, anorexia, vomiting, diarrhea, cyanosis, convulsions and coma
• ~7 cases reported annually
La Crosse Encephalitis (LAC)
• California serogroup virus
• Maintained by Aedes triseriatusmosquitoes small mammals
• Symptoms• Fever, headache, nausea, vomiting, fatigue, lethargy, seizures, coma and paralysis
• ~72 cases reported annually
• Testing available at CDC and commercial labs
Arboviral Surveillance
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Comparison of Arboviruses Transmitted Locally
Agent Incubation period Severe disease more common in patients Mortality rate
WNV 2‐15 days ≥50 years old or immunocompromised 3‐15% of patients with encephalitis
SLE 5‐7 days ≥60 years old 2‐20% of those with encephalitis
EEE 4‐10 days <15 years old or >50 years old 50% of those with encephalitis, permanent disability common
LAC 5‐15 days <16 years old 1%, can be long term problems
2016 Arboviral Surveillance Reporthttp://ldh.la.gov/index.cfm/newsroom/detail/4306
2016 Arboviral Surveillance Reporthttp://ldh.la.gov/index.cfm/newsroom/detail/4306
Arboviral Surveillance
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Jamestown Canyon Encephalitis (JCV)
• California serogroup virus
• LA identified 1st case in 2017• 31 reported cases between 2000‐2013
• Maintained in nature by white‐tailed deer and mosquitoes (unknown species)
• Testing available at CDC• In process of validation at LA OPH Lab
Enhanced Surveillance for JCV
• WNV IgG+ and WNV IgM‐ AND
• Neurologic symptoms AND
• Aseptic meningitis
• Testing serum/CSF at OPH Lab for WNV, SLE and EEE• Once validated, will test for JCV
Arboviral Diseases Imported to Louisiana
• Chikungunya virus
• Dengue virus
• Zika virus
Chikungunya Distribution
Dengue Distribution
Zika Distribution
Arboviral Surveillance
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Chikungunya• Alphavirus
• Transmission:• Nonhuman and human primates are main reservoirs• Bloodborne transmission is possible• Maternal‐fetal transmission possible, highest risk when mother is viremic at time of delivery
• Typically associated with large outbreaks with high attack rates (can affect between 1/3 and 3/4 of local population)
• Most outbreaks during tropical rainy seasons, unless open water containers used near human habitations
• In recent history, was only found in Africa, Asia, Europe, Pacific Islands, and Indian Ocean Islands
• 2006‐2013, average of 28 imported cases per year
• Re‐introduced to the Americas in 2013
• Imported cases in most states, only local transmission has been in Florida (2014) and Texas (2015)
Chikungunya
• Incubation period: 3‐7 Days
• Viremia: first 2‐6 Days of illness
• ~72‐97% of infected individuals have symptoms
• Symptoms: Last 7‐10 Days• Sudden onset of high fever, can be biphasic• Joint Pains, bilateral, symmetric (typically hands and feet)• Headache, myalgia, arthritis, nausea, maculopapular rash
• Serious Complications• Myocarditis, ocular disease, acute renal disease, bullous lesions, neurologic disease
• Increased Risk: neonates, >65 years, underlying medical conditions
Dengue• Transmission: bloodborne, breastmilk possible
• 4 Related Flaviviruses, Dengue 1, 2, 3, and 4• Infection with 1 species provides immunity from that one, but makes individual more susceptible to hemorrhagic fever if infected with another
• Endemic throughout tropics and subtropics
• One of leading causes of febrile illness among travelers in Americas and Southeast Asia
Dengue• Incubation: 5‐7 Days
• Only 25% Symptomatic, 3 Phases1. Febrile (2‐7 days), biphasic – headache, retro‐orbital pain,
muscle/joint/bone pain, rash. Signs of shock warn of progression to critical
2. Critical (1‐2 days) – defervescence, substantial plasma leakage can lead to further complications; hypotension can develop and lead to shock; also possible hemorrhagic manifestations; encephalitis is uncommon
3. Convalescence – hemodynamic status stabilizes, white cell counts usually rise, rash may develop
• 5% of symptomatic individuals develop severe, life‐threatening illness
Arboviral Surveillance
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Zika• Flavivirus
• Zika virus first discovered in 1947 in Uganda through Yellow Fever monitoring network
• 2013‐2014: Outbreak in French Polynesia
• 2015: First reports of locally transmitted cases in Brazil, gradual spread throughout the Americas and the Caribbean
• 2016: First reports of locally transmitted cases in Miami‐Dade County, Florida, and then Brownsville, Texas (No longer considered local transmission areas)
Zika
• Transmission:• Bloodborne• Sexual Transmission
• Has been found in genital fluids up to 6 months for men and 2 months for women
• Mother to Infant• “Never before has a mosquito bite caused such a defect.” Dr. Frieden CDC
• Incubation: 3‐14 Days
• Viremia: 2‐7 Days
• Symptom duration: Few days to 1 week
Zika• Associated Symptoms:
• Fever• Arthralgia• Conjunctivitis• Rash• Myalgia• Headache
• Discoveries During Brazil 2015 Response*• Association with Guillain‐Barré Syndrome• Association with fetal microcephaly and Congenital Zika Syndrome
*These complications likely not detected previously due to small case counts in previous outbreaks
Arboviral Surveillance
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Diagnosis• Difficult due to mildness of illness, similarities with other illnesses, and complication of tests
• Differential Diagnosis:
• Zika• Dengue• Chikungunya• Leptospirosis• Malaria• Rickettsia• Group A
Streptococcus
• Rubella• Measles• Parvovirus• Enterovirus• Adenovirus• Other
alphaviruses
2016 Arboviral Surveillance Reporthttp://ldh.la.gov/index.cfm/newsroom/detail/4306
Laboratory Diagnostics• Virus
• Typically only detectable at beginning of illness
• Antibodies:• Humoral immunity necessary for initial containment and clearance of infection, but also protection against reinfection
• IgM first antibody produced, common in acute infections• IgG associated with past infections, confers protection from subsequent reinfection
• Diagnosis:• Serology (antibodies) and nucleic acid tests (virus)
• Even if antibodies are detectable, unclear if those are specific for and neutralize virus • Serological cross‐reactivity – If same genus have similar antigens
• Previous infection with Dengue or SLE• YF Vaccines (military)
Testing at State Lab• Zika – Emergency Use Authorization – individuals need to feet CDC’s testing criteria to qualify for testing
• Trioplex RT‐PCR• Chikungunya, Dengue, and Zika concurrently• Current viremia• Useful due to similarities of clinical manifestations and epidemiological factors
• IgM• Individually available• Checks for antibodies/immune response• Asymptomatic: Dengue and Zika• Symptomatic: Chikungunya, Dengue, and Zika
• PRNT (Plaque Reduction Neutralization Test)• CDC’s confirmatory test for specific neutralizing antibodies
Arboviral Surveillance
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Zika Pregnancy Registry Updates
• Current pediatric follow‐up at 2, 6 and 12 months
• Extending to 18 and 24 months• Increasing surveillance to monitor for birth defects• Able to distinguish between maternal and infant antibodies ≥18 months
ZPR Recommendations
• Screening pregnant women for Zika at all OB visits
• Increasing communication between obstetric and pediatric health care providers• Pediatricians are unaware of mother’s status and infant not tested
Updated Recommendations
• Infants with clinical findings consistent with congenital Zika syndrome born to mothers with possible Zika virus exposure in pregnancy• Routine testing is recommended
• Testing CSF should be considered IF obtained for other purposes
• Head ultrasound and comprehensive ophthalmologic exam performed by age 1 month• Referred for automated auditory brainstem response (ABR) by age 1 month if hearing screen passed
Arboviral Surveillance
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Updated Recommendations
• Infants without clinical findings consistent with congenital Zika syndrome born to mothers with laboratory evidence of possible Zika virus infection during pregnancy• Routine testing is recommended
• If adequately performed then an infection is unlikely
• Head ultrasound and comprehensive ophthalmologic exam performed by age 1 month• Referred for automated ABR by age 1 month if hearing screen passed
Updated Recommendations
• Infants without clinical findings consistent with congenital Zika syndrome born to mothers with possible Zika virus exposure in pregnancy but without laboratory evidence of possible Zika virus infection during pregnancy• Mothers with negative lab results
• Routine testing is not recommended
• Mothers never tested during pregnancy• Please call ID Epi to evaluate scenario
Questions
• Julius L. Tonzel• (504) 568‐8296• Julius.tonzel@la.gov
• Sean Simonson• (504) 568‐8342• Sean.simonson@la.gov
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