Outbreak Investigation Guidance for Vectorborne Diseases

Transcription

1 COMMUNICABLE DISEASE OUTBREAK MANUAL New Jersey s Public Health Response APPENDIX T3: EXTENDED GUIDANCE Outbreak Investigation Guidance for Vectorborne Diseases As per N.J.A.C. 8:57, viruses that are transmitted by the bite of an infected mosquito (i.e., arboviral diseases) must be reported within 24 hours of clinician diagnosis and 72 hours of laboratory identification. To date, the only arboviral diseases routinely identified in New Jersey are West Nile virus (WNV) and Eastern equine encephalitis (EEE). Also included in this reportable disease category is dengue (DEN), where cases are reported annually in residents returning from international travel or exposure in south Florida and Puerto Rico; chikungunya (CHIKV), where cases are reported every few years in residents traveling to Europe and Asia; St. Louis encephalitis (SLE) and LaCrosse virus encephalitis (LAC), which have been reported from states in the central and south central United States (U.S.); and Powassan virus (POW), which is the only arbovirus that is transmitted by a tick rather than a mosquito, and has been reported from parts of the Northern U.S., including northern New York. In addition to arboviral diseases, other mosquito-borne diseases that are reportable in New Jersey include malaria, where cases occur primarily in sub-saharan Africa and parts of northern South America, southern Asia and Indonesia; and yellow fever, which may occur in travelers to sub-saharan Africa and South America. Although there may be counties with hotspots of WNV activity in a given season, outbreaks of WNV or EEE are rare, as the viruses are endemic in nature and there is no standardized threshold of expected cases per season. Public health investigation of WNV and EEE is important to minimize the number of human and equine cases found annually in New Jersey, as information obtained from these investigations allows local mosquito control agencies to implement focused mosquito surveillance and abatement measures. Public health investigation of non-endemic arboviral diseases (DEN, CHIKV, SLE, LAC, POW) and malaria allows public health and mosquito control professionals to recommend prevention measures that minimize the possibility of an infected traveler transmitting the pathogen to local mosquitoes and posing a risk of autocthonous transmission. As such, case investigations for mosquito-borne diseases should remain a priority, even though outbreaks rarely occur. Other vectorborne diseases that are reportable as per N.J.A.C. 8:57 are bacterial and protozoan tickborne diseases, including babesiosis, ehrlichiosis / anaplasmosis, Lyme disease, and Rocky mountain Page 1 of 5

2 spotted fever (RMSF). Many of these pathogens are endemic in New Jersey and result in widespread cases among individuals exposed to ticks. Similar to mosquito-borne diseases, outbreaks are rare. Public health investigations provide information on exposure and risk factors that help guide prevention materials and health alerts for clinicians in areas where cases are more likely to be seen. In addition, timely investigations allow public health professionals to learn more about emerging pathogens such as babesiosis, and track the expanding range of certain ticks that may become established in new areas throughout the state. Guidance for investigating routine cases of vectorborne diseases can be found in the NJDOH Communicable Disease Manual. Information included in this manual focuses on three special situations: an outline of how WNV cases are investigated, counted and communicated to internal and external stakeholders, given the high profile nature of these cases; and instructions on how to investigate cases of transfusion- and transplant-transmitted vectorborne diseases. For all other nonroutine circumstances, including reporting a suspected novel vectorborne disease, local transmission of a travel-related mosquito-borne disease, or a higher than expected occurrence of a vectorborne disease, local health departments should contact the NJDOH Vectorborne Disease Program at (609) Overview of WNV / EEE Case Investigation, Classification and Communication 1. Suspected cases of WNV and EEE are frequently identified through laboratory reports sent to the LHD or electronically reported on the NJDOH Communicable Disease Reporting and Surveillance System (CDRSS). Lab reports with evidence of WNV or EEE IgM antibodies require further investigation. Lab reports with evidence of WNV or EEE IgG antibodies only are indicative of previous exposure or past infection and may be shredded or closed as not a case. Occasionally, suspect cases of WNV and EEE may be sent directly to the NJDOH PHEL for testing; these cases will not be entered into CDRSS unless a positive result is reported by PHEL. 2. For all suspect cases of WNV and EEE, the LHD should obtain the following information: a. Complete patient demographics, including age, gender and street address. The information obtained will be used by mosquito control to perform additional mosquito surveillance activities. Be specific, as a post office box is not sufficient to initiate these activities. b. Symptom onset date and a list of signs and symptoms, including the measured value of any self- or clinician-reported fever. c. Report any co-morbidities or immune-compromising conditions. d. Onset and discharge date of hospitalization, admitting diagnosis, status of patient throughout the hospitalization (e.g., ICU, breathing tube) and discharge status (e.g., discharged home, discharged to rehabilitative facility). Continue to follow the progress of Page 2 of 5

3 the patient throughout their hospitalization; the case will not be closed until a discharge date and final status have been recorded in CDRSS. e. Detailed information regarding outdoor exposure 15 days prior to symptom onset. If the person is immune-compromised, the exposure period is extended to 30 days prior to symptom onset. Exposure information should include addresses when available, travel throughout the state and local activities (e.g., gardening in yard). If the person was exposed out of state, this information should be noted, along with the location of travel. The NJDOH vectorborne disease epidemiologist will share this information with health departments in other states. f. Report whether the person donated or received blood, organs or blood products. g. Report if the person is pregnant or breast-feeding. 3. As the LHD is investigating the case, the NJDOH vectorborne disease epidemiologist will be monitoring the case on CDRSS and communicating de-identified information to the NJ Department of Environmental Protection (NJDEP) Office of Mosquito Control Coordination and county mosquito agency. The NJDEP and county mosquito control agency will use the deidentified information to initiate mosquito surveillance and abatement activities in the area where the person resides or was potentially exposed. The LHD is encouraged to also communicate de-identified case information with their local mosquito control agency, however, it s important to emphasize that all information is confidential and should not be shared with other officials in county government, unless they are directly involved in surveillance and abatement activities. It is also important to note that case identification will not be released to the media until the investigation is complete and the NJDOH has reviewed the information in CDRSS. 4. The NJDOH will evaluate all cases and determine if they meet case definition for confirmed or probable WNV or EEE. Once the NJDOH classifies a case of WNV, they will notify the LHD and county mosquito control agency before adding the case to the NJDOH WNV website and other aggregated, de-identified reports. During the WNV season, the NJDOH vectorborne disease epidemiologist will update human case counts on a weekly basis; these updates are posted on the NJDOH WNV website and sent via LINCS to all LHDs. For ease of reporting, both confirmed and probable cases will be reported together as one number. LHDs are encouraged to contact the NJDOH vectorborne epidemiologist before issuing a press release or responding to a request from the media, to ensure statistics are accurate and consistent. The NJDOH vectorborne disease epidemiologist can be reached by calling the NJDOH vectorborne disease program at (609) The NJDOH will upload de-identified WNV and other arboviral disease data to ArboNET, the CDC s national database. Data is uploaded to ArboNET weekly, however, the date for the NJDOH weekly WNV report may differ from the CDC ArboNET report; as such, statistics may differ between the CDC and NJDOH websites. Again, LHDs are encouraged to contact the NJDOH vectorborne disease epidemiologist for current case totals. Page 3 of 5

4 6. In the event that a county or municipality is identified as having unusually high WNV or EEE activity, the NJDOH and NJDEP will work with the LHD and county mosquito control agency to implement additional surveillance, abatement and prevention initiatives as needed. There is no pre-determined or standardized threshold of human cases, positive birds or positive mosquito pools that would indicate unusually high WNV or EEE activity. As such, it is important that LHDs and county mosquito control agencies maintain a working relationship and routinely communicate with the NJDOH and NJDEP to identify any unusually high increases in viral activity. Guidelines for Investigating Transfusion- and Transplantation-Transmitted Cases of Vectorborne Diseases 1. The following vectorborne diseases have been implicated in cases of confirmed or probable transfusion- and/or transplant-associated transmission: WNV, malaria and babesiosis, anaplasmosis and ehrlichiosis. Vectorborne diseases that have been implicated in cases of confirmed or probable transplant-associated transmission include WNV and ehrlichiosis. All blood donations in the U.S. are currently screened for WNV using nucleic acid amplification testing (NAT), however the method used involves pooling samples prior to testing and donors with early or low-levels or viremia may escape detection. There is no FDA-approved test for screening blood donations for malaria or babesiosis. Pre-donation screening for blood donors include questions regarding babesiosis; individuals previously diagnosed are asked to refrain from blood donation indefinitely. Pre-donation screening questionnaires also address malaria, where travelers to an area with malaria are deferred from donating blood for one year after their return; former residents of areas where malaria is present are deferred for three years; and individuals diagnosed with malaria cannot donate blood for three years after treatment, during which time they must remain free of symptoms. As such, the risk of contracting malaria and babesiosis following receipt of a blood donation is low. Donated organs are not tested for vectorborne diseases prior to transplantation, as the risk of transmission is very low and the delay in testing may reduce the viability of transplantation. 2. All suspected cases of WNV, malaria and babesiosis should be investigated in a timely manner to ensure suspected transfusion- and transplant-associated transmission cases are identified as soon as possible, and any potentially contaminated product is removed. a. For WNV, confirm that outdoor exposure occurred during the 15 days prior to symptom onset, or 30 days if the individual is immune-compromised. b. For malaria, confirm that travel history is present during the three months prior to symptom onset. The CDC website for malaria contains the most recent information of where malaria is endemic or present in local mosquito populations. c. For babesiosis, confirm that outdoor exposure occurred during the eight weeks prior to symptom onset in a state where babesiosis has been implicated in locally-acquired cases. Babesiosis is present in Ixodes scapularis populations throughout New Jersey. Page 4 of 5

5 3. In cases where no outdoor exposure or travel history is present, the LHD should contact the NJDOH vectorborne disease program at (609) The NJDOH vectorborne disease epidemiologist will work with the LHD to gather further information about possible receipt of a transfusion or transplant. The following steps would be undertaken to investigate cases where an individual received donated blood or organs: a. The LHD should obtain clinical information including co-morbidities, hospitalizations and treatment during the incubation period for the specific pathogen. The incubation period may be extended for immune-compromised individuals. b. A linelist should be created for any blood or blood product donations that were received during the incubation period. The linelist should include variables such as the hospital or facility where the individual was transfused; the date of the transfusion; the blood bank where the donation originated from; unique identifier assigned to the donation at the blood bank; date of any tests performed on the donation; type of test performed on the donation and whether method used individual donations or pooled donors; result of tests performed on the donation; and laboratory where testing was performed. In addition, for each donation, the linelist should indicate whether an aliquot is available for further testing at the NJDOH PHEL and whether any additional product remains at the blood bank for further distribution. c. The NJDOH will work with the blood bank to request any additional product be quarantined until the public health investigation is complete, facilitate testing of donation aliquots to establish a potential link to a suspected human case of infection. d. The NJDOH will work with the blood bank and the CDC to initiate a traceback of the blood donation, blood product or organ donation if appropriate. Cases of transfusionand transplant-associated transmission are rarely confirmed and frequently involve donations that have already been distributed. The risk of transmission through a contaminated blood or organ product is very low, so notification of product recipients is rarely recommended. The NJDOH and CDC will work with the LHD and blood bank if notification is deemed appropriate. June 2013 Download the full Communicable Disease Outbreak: New Jersey s Public Health Response at Page 5 of 5