Arboviral and other vector-borne diseases

May has arrived, and for the majority of your patients it signals the end of the school year and the beginning of summer vacation. Zika virus is on the minds of most people since its arrival to the Western Hemisphere in March 2015. With the fluidity of this outbreak and almost daily news updates and recommendations, many parents have voiced or will be voicing concerns regarding summer travel destinations.

Many concerns about Zika virus have been previously addressed in this column (“Zika virus: More questions than answers?” by Dr. Kristina Bryant). However, if the decision is to avoid international travel because of the ongoing Zika outbreak, it doesn’t mean your patients get a free pass and will not have to be concerned about acquiring any infectious diseases. They still need to be vigilant about avoiding those pesky vectors that transmit arboviruses and other vector-borne diseases that occur in the United States.

Arboviruses are transmitted by mosquitoes, ticks, or fleas. Most infections are subclinical. If symptoms develop, they are manifested by a generalized febrile illness including fever, headache, myalgia, arthralgia, and rash. Hemorrhagic fever (dengue) or neuroinvasive disease can include aseptic meningitis, encephalitis, or acute flaccid paralysis. Neuroinvasive disease rarely occurs with dengue, Colorado tick fever, and chikungunya infections.

While more than 100 arboviruses can cause infection, some of the more common arboviruses associated with human disease include West Nile, first detected in the United States in 1999 and chikungunya, first reported in the Americas in 2013 with local transmission documented in Florida, Puerto Rico, and the U.S. Virgin Islands in 2014. It is estimated that dengue causes over 100 million cases worldwide annually. Almost 40% of the world’s inhabitants live in endemic areas. The majority of cases on the U.S. mainland are imported. However, it is endemic in all U.S. territories including Guam, American Samoa, the U.S. Virgin Islands, and Puerto Rico. Between September 2015 and March 2016, Hawaii experienced a dengue outbreak involving 264 individuals including 46 children. As of April 16, 2016, there were no infectious individuals on the island.

Courtesy Wikimedia Commons/Muhammad Mahdi Karim/Creative Commons License

Other domestic arboviruses causing disease include St. Louis, Eastern, and Western Equine encephalitis, La Crosse encephalitis, Colorado tick fever, and Powassan virus. All are transmitted by mosquitoes with the exception of Powassan and Colorado tick fever, which are transmitted by ticks. The numbers of cases nationally are much lower for these diseases, compared with West Nile, dengue, and chikungunya. National and state-specific information is available for domestic arboviruses at diseasemaps.usgs.gov/mapviewer. Data is compiled by ArboNET, a national arboviral surveillance system that is managed by the Centers for Disease Control and Prevention (CDC) in conjunction with state health departments. Not only is human disease monitored, but it also maintains data on viremic blood donors, dead birds, mosquitoes, veterinary disease cases, and sentinel animals.

Spring and summer are the most active seasons for ticks. Bacterial and spirochetal diseases transmitted by them include rickettsial diseases such as Rocky Mountain Spotted Fever, ehrlichiosis, and anaplasmosis. Tularemia in addition to Lyme and tick-borne relapsing fever are also transmitted by ticks. Babesiosis, which is due to a parasite, and southern tick-associated rash illness (STARI), whose causative agent is yet to be determined, are two additional tick-related diagnoses.

Of note, dengue, chikungunya, and Zika are all transmitted by infected Aedes mosquitoes. There is no enzootic cycle. Just human-mosquito-human transmission. In contrast, West Nile virus is transmitted by Culex mosquitoes in an enzootic cycle between an avian reservoir and humans.

Treatment

There is no specific treatment for arboviral infections. The primary goal is relief of symptoms with fluids, bed rest, and analgesics. For bacterial vector-borne diseases, antibiotic therapy is indicated and is based on the specific pathogen. Doxycycline is the drug of choice for treatment of suspected and confirmed Rocky Mountain Spotted Fever, ehrlichiosis, and anaplasmosis even in children less than 8 years of age. Delay in initiation of antimicrobial therapy pending definitive diagnosis may lead to an adverse outcome. It is also the drug of choice for tick-borne relapsing fever.

Lyme disease is also responsive to antibiotic treatment. Therapy is based on the disease category. (Lyme disease in “Red Book: 2015 Report of the Committee on Infectious Diseases,” [Elk Grove Village, Ill.: American Academy of Pediatrics, 2015, pp. 516-25]).

STARI clinically presents with a lesion that resembles erythema migrans in southern and southeastern states. However, it has not been associated with any of the complications reported with disseminated Lyme disease. Treatment is not recommended.

Tularemia and babesiosis are both responsive to antimicrobial therapy and would best be managed in consultation with an infectious disease physician.

A handy, concise, up to date reference guide about all of the tick-borne diseases including photographs is available at the App Store. The Tickborne Diseases App was developed by the CDC and it is free!

Prevention

The cornerstone of disease prevention is avoidance of mosquito and tick bites, in addition to eliminating mosquito breeding sites. Ticks are generally found near the ground, in brushy or wooded areas. They usually wait for a potential host to brush against them. When this happens, they climb onto the host and find a site to attach.

Is there a role for antimicrobial prophylaxis once a tick has been discovered? There is no data to support antimicrobial prophylaxis to prevent Rocky Mountain spotted fever, ehrlichiosis, and anaplasmosis. Prophylaxis with doxycycline or ciprofloxacin is recommended for children and adults after exposure to an intentional release of tularemia and for laboratory workers after inadvertent exposure. For prevention of Lyme disease, a single dose of doxycycline (4 mg/kg, max dose 200 mg) may be offered under limited conditions: The patient is at least 8 years of age, resides in an area where Lyme is highly endemic, the tick removed was engorged, therapy can be initiated within 72 hours after tick removal, and the estimated time of attachment was at least 36 hours. There is inadequate data on the use of amoxicillin.

Remember, not all mosquitoes are alike. Those that transmit chikungunya, dengue, and Zika (Aedes mosquitoes) are primarily daytime mosquitoes, but also can bite at night. West Nile is transmitted by Culex mosquitoes, which feed from dusk to dawn.

Here are some tips to share with your patients that should decrease their chances of acquiring a mosquito or tick-borne disease:

• Apply mosquito repellent only to intact exposed skin when outdoors. Most repellents can be safely used on children at least 2 months of age and older. Avoid applying repellent directly on the child’s hand. Use at least a 20% DEET (N,N-diethyl-meta-toluamide) containing product. Other Environmental Protection Agency–registered repellents are an alternative (Additional information is available at http://www2.epa.gov/insect-repellents). Products containing oil of lemon eucalyptus (OLE) or p-Menthane-3,8-diol (PMD) should not be used on children under 3 years of age.

• Apply permethrin to clothing, hats, boots, and so on. It is designed to repel mosquitoes and ticks. It can last for several washings. It is ideal to spray over nets covering carriers in children younger than 2 months of age.

• Wear long-sleeved shirts and long pants tucked inside of socks when hiking.

• Check for ticks daily, especially under the arms, behind the ears, around the waist, behind the knees, and inside belly buttons after outdoor activities.

• Have your patients learn how to effectively remove a tick. With a fine tipped tweezer, grasp the tick as close to the skin as possible and pull straight up with even pressure. Do not twist or jerk the tick. Do not squash the tick. Place it in a bag and dispose of it. Clean the site after removal with alcohol, iodine, or soap and water.

• Encourage families to mosquito proof their home by using screens on windows and doors, and using air conditioning when available.

• Empty and scrub all items that contain water such as birdbaths, planters, or wading pools around the outside of the home at least weekly because mosquitoes lay eggs in or near free standing water.

• Dogs and cats should be treated for ticks as recommended by the veterinarian.

The impact of the ongoing Zika virus outbreak is uncertain. While it may have an impact on those planning international travel now and in the near future, several arboviral and vector-borne diseases currently exist in the United States. Encouraging our patients to practice interventions to prevent mosquito and tick bites now will also serve to protect them if Zika virus becomes established in the Aedes mosquitoes here in the future and/or if they have plans for international travel. For up to date information on Zika virus for yourself and your patients, visit www.cdc.gov/zika.

Bonnie M. Word, M.D., is a pediatric infectious disease specialist and director of the Houston Travel Medicine Clinic. She said she had no relevant financial disclosures. Email Dr. Word at pdnews@frontlinemedcom.com.

May has arrived, and for the majority of your patients it signals the end of the school year and the beginning of summer vacation. Zika virus is on the minds of most people since its arrival to the Western Hemisphere in March 2015. With the fluidity of this outbreak and almost daily news updates and recommendations, many parents have voiced or will be voicing concerns regarding summer travel destinations.

Many concerns about Zika virus have been previously addressed in this column (“Zika virus: More questions than answers?” by Dr. Kristina Bryant). However, if the decision is to avoid international travel because of the ongoing Zika outbreak, it doesn’t mean your patients get a free pass and will not have to be concerned about acquiring any infectious diseases. They still need to be vigilant about avoiding those pesky vectors that transmit arboviruses and other vector-borne diseases that occur in the United States.

Arboviruses are transmitted by mosquitoes, ticks, or fleas. Most infections are subclinical. If symptoms develop, they are manifested by a generalized febrile illness including fever, headache, myalgia, arthralgia, and rash. Hemorrhagic fever (dengue) or neuroinvasive disease can include aseptic meningitis, encephalitis, or acute flaccid paralysis. Neuroinvasive disease rarely occurs with dengue, Colorado tick fever, and chikungunya infections.

While more than 100 arboviruses can cause infection, some of the more common arboviruses associated with human disease include West Nile, first detected in the United States in 1999 and chikungunya, first reported in the Americas in 2013 with local transmission documented in Florida, Puerto Rico, and the U.S. Virgin Islands in 2014. It is estimated that dengue causes over 100 million cases worldwide annually. Almost 40% of the world’s inhabitants live in endemic areas. The majority of cases on the U.S. mainland are imported. However, it is endemic in all U.S. territories including Guam, American Samoa, the U.S. Virgin Islands, and Puerto Rico. Between September 2015 and March 2016, Hawaii experienced a dengue outbreak involving 264 individuals including 46 children. As of April 16, 2016, there were no infectious individuals on the island.

Courtesy Wikimedia Commons/Muhammad Mahdi Karim/Creative Commons License

Other domestic arboviruses causing disease include St. Louis, Eastern, and Western Equine encephalitis, La Crosse encephalitis, Colorado tick fever, and Powassan virus. All are transmitted by mosquitoes with the exception of Powassan and Colorado tick fever, which are transmitted by ticks. The numbers of cases nationally are much lower for these diseases, compared with West Nile, dengue, and chikungunya. National and state-specific information is available for domestic arboviruses at diseasemaps.usgs.gov/mapviewer. Data is compiled by ArboNET, a national arboviral surveillance system that is managed by the Centers for Disease Control and Prevention (CDC) in conjunction with state health departments. Not only is human disease monitored, but it also maintains data on viremic blood donors, dead birds, mosquitoes, veterinary disease cases, and sentinel animals.

Spring and summer are the most active seasons for ticks. Bacterial and spirochetal diseases transmitted by them include rickettsial diseases such as Rocky Mountain Spotted Fever, ehrlichiosis, and anaplasmosis. Tularemia in addition to Lyme and tick-borne relapsing fever are also transmitted by ticks. Babesiosis, which is due to a parasite, and southern tick-associated rash illness (STARI), whose causative agent is yet to be determined, are two additional tick-related diagnoses.

Of note, dengue, chikungunya, and Zika are all transmitted by infected Aedes mosquitoes. There is no enzootic cycle. Just human-mosquito-human transmission. In contrast, West Nile virus is transmitted by Culex mosquitoes in an enzootic cycle between an avian reservoir and humans.

Treatment

There is no specific treatment for arboviral infections. The primary goal is relief of symptoms with fluids, bed rest, and analgesics. For bacterial vector-borne diseases, antibiotic therapy is indicated and is based on the specific pathogen. Doxycycline is the drug of choice for treatment of suspected and confirmed Rocky Mountain Spotted Fever, ehrlichiosis, and anaplasmosis even in children less than 8 years of age. Delay in initiation of antimicrobial therapy pending definitive diagnosis may lead to an adverse outcome. It is also the drug of choice for tick-borne relapsing fever.

Lyme disease is also responsive to antibiotic treatment. Therapy is based on the disease category. (Lyme disease in “Red Book: 2015 Report of the Committee on Infectious Diseases,” [Elk Grove Village, Ill.: American Academy of Pediatrics, 2015, pp. 516-25]).

STARI clinically presents with a lesion that resembles erythema migrans in southern and southeastern states. However, it has not been associated with any of the complications reported with disseminated Lyme disease. Treatment is not recommended.

Tularemia and babesiosis are both responsive to antimicrobial therapy and would best be managed in consultation with an infectious disease physician.

A handy, concise, up to date reference guide about all of the tick-borne diseases including photographs is available at the App Store. The Tickborne Diseases App was developed by the CDC and it is free!

Prevention

The cornerstone of disease prevention is avoidance of mosquito and tick bites, in addition to eliminating mosquito breeding sites. Ticks are generally found near the ground, in brushy or wooded areas. They usually wait for a potential host to brush against them. When this happens, they climb onto the host and find a site to attach.

Is there a role for antimicrobial prophylaxis once a tick has been discovered? There is no data to support antimicrobial prophylaxis to prevent Rocky Mountain spotted fever, ehrlichiosis, and anaplasmosis. Prophylaxis with doxycycline or ciprofloxacin is recommended for children and adults after exposure to an intentional release of tularemia and for laboratory workers after inadvertent exposure. For prevention of Lyme disease, a single dose of doxycycline (4 mg/kg, max dose 200 mg) may be offered under limited conditions: The patient is at least 8 years of age, resides in an area where Lyme is highly endemic, the tick removed was engorged, therapy can be initiated within 72 hours after tick removal, and the estimated time of attachment was at least 36 hours. There is inadequate data on the use of amoxicillin.

Remember, not all mosquitoes are alike. Those that transmit chikungunya, dengue, and Zika (Aedes mosquitoes) are primarily daytime mosquitoes, but also can bite at night. West Nile is transmitted by Culex mosquitoes, which feed from dusk to dawn.

Here are some tips to share with your patients that should decrease their chances of acquiring a mosquito or tick-borne disease:

• Apply mosquito repellent only to intact exposed skin when outdoors. Most repellents can be safely used on children at least 2 months of age and older. Avoid applying repellent directly on the child’s hand. Use at least a 20% DEET (N,N-diethyl-meta-toluamide) containing product. Other Environmental Protection Agency–registered repellents are an alternative (Additional information is available at http://www2.epa.gov/insect-repellents). Products containing oil of lemon eucalyptus (OLE) or p-Menthane-3,8-diol (PMD) should not be used on children under 3 years of age.

• Apply permethrin to clothing, hats, boots, and so on. It is designed to repel mosquitoes and ticks. It can last for several washings. It is ideal to spray over nets covering carriers in children younger than 2 months of age.

• Wear long-sleeved shirts and long pants tucked inside of socks when hiking.

• Check for ticks daily, especially under the arms, behind the ears, around the waist, behind the knees, and inside belly buttons after outdoor activities.

• Have your patients learn how to effectively remove a tick. With a fine tipped tweezer, grasp the tick as close to the skin as possible and pull straight up with even pressure. Do not twist or jerk the tick. Do not squash the tick. Place it in a bag and dispose of it. Clean the site after removal with alcohol, iodine, or soap and water.

• Encourage families to mosquito proof their home by using screens on windows and doors, and using air conditioning when available.

• Empty and scrub all items that contain water such as birdbaths, planters, or wading pools around the outside of the home at least weekly because mosquitoes lay eggs in or near free standing water.

• Dogs and cats should be treated for ticks as recommended by the veterinarian.

The impact of the ongoing Zika virus outbreak is uncertain. While it may have an impact on those planning international travel now and in the near future, several arboviral and vector-borne diseases currently exist in the United States. Encouraging our patients to practice interventions to prevent mosquito and tick bites now will also serve to protect them if Zika virus becomes established in the Aedes mosquitoes here in the future and/or if they have plans for international travel. For up to date information on Zika virus for yourself and your patients, visit www.cdc.gov/zika.

Bonnie M. Word, M.D., is a pediatric infectious disease specialist and director of the Houston Travel Medicine Clinic. She said she had no relevant financial disclosures. Email Dr. Word at pdnews@frontlinemedcom.com.

May has arrived, and for the majority of your patients it signals the end of the school year and the beginning of summer vacation. Zika virus is on the minds of most people since its arrival to the Western Hemisphere in March 2015. With the fluidity of this outbreak and almost daily news updates and recommendations, many parents have voiced or will be voicing concerns regarding summer travel destinations.

Many concerns about Zika virus have been previously addressed in this column (“Zika virus: More questions than answers?” by Dr. Kristina Bryant). However, if the decision is to avoid international travel because of the ongoing Zika outbreak, it doesn’t mean your patients get a free pass and will not have to be concerned about acquiring any infectious diseases. They still need to be vigilant about avoiding those pesky vectors that transmit arboviruses and other vector-borne diseases that occur in the United States.

Arboviruses are transmitted by mosquitoes, ticks, or fleas. Most infections are subclinical. If symptoms develop, they are manifested by a generalized febrile illness including fever, headache, myalgia, arthralgia, and rash. Hemorrhagic fever (dengue) or neuroinvasive disease can include aseptic meningitis, encephalitis, or acute flaccid paralysis. Neuroinvasive disease rarely occurs with dengue, Colorado tick fever, and chikungunya infections.

While more than 100 arboviruses can cause infection, some of the more common arboviruses associated with human disease include West Nile, first detected in the United States in 1999 and chikungunya, first reported in the Americas in 2013 with local transmission documented in Florida, Puerto Rico, and the U.S. Virgin Islands in 2014. It is estimated that dengue causes over 100 million cases worldwide annually. Almost 40% of the world’s inhabitants live in endemic areas. The majority of cases on the U.S. mainland are imported. However, it is endemic in all U.S. territories including Guam, American Samoa, the U.S. Virgin Islands, and Puerto Rico. Between September 2015 and March 2016, Hawaii experienced a dengue outbreak involving 264 individuals including 46 children. As of April 16, 2016, there were no infectious individuals on the island.

Courtesy Wikimedia Commons/Muhammad Mahdi Karim/Creative Commons License

Other domestic arboviruses causing disease include St. Louis, Eastern, and Western Equine encephalitis, La Crosse encephalitis, Colorado tick fever, and Powassan virus. All are transmitted by mosquitoes with the exception of Powassan and Colorado tick fever, which are transmitted by ticks. The numbers of cases nationally are much lower for these diseases, compared with West Nile, dengue, and chikungunya. National and state-specific information is available for domestic arboviruses at diseasemaps.usgs.gov/mapviewer. Data is compiled by ArboNET, a national arboviral surveillance system that is managed by the Centers for Disease Control and Prevention (CDC) in conjunction with state health departments. Not only is human disease monitored, but it also maintains data on viremic blood donors, dead birds, mosquitoes, veterinary disease cases, and sentinel animals.

Spring and summer are the most active seasons for ticks. Bacterial and spirochetal diseases transmitted by them include rickettsial diseases such as Rocky Mountain Spotted Fever, ehrlichiosis, and anaplasmosis. Tularemia in addition to Lyme and tick-borne relapsing fever are also transmitted by ticks. Babesiosis, which is due to a parasite, and southern tick-associated rash illness (STARI), whose causative agent is yet to be determined, are two additional tick-related diagnoses.

Of note, dengue, chikungunya, and Zika are all transmitted by infected Aedes mosquitoes. There is no enzootic cycle. Just human-mosquito-human transmission. In contrast, West Nile virus is transmitted by Culex mosquitoes in an enzootic cycle between an avian reservoir and humans.

Treatment

There is no specific treatment for arboviral infections. The primary goal is relief of symptoms with fluids, bed rest, and analgesics. For bacterial vector-borne diseases, antibiotic therapy is indicated and is based on the specific pathogen. Doxycycline is the drug of choice for treatment of suspected and confirmed Rocky Mountain Spotted Fever, ehrlichiosis, and anaplasmosis even in children less than 8 years of age. Delay in initiation of antimicrobial therapy pending definitive diagnosis may lead to an adverse outcome. It is also the drug of choice for tick-borne relapsing fever.

Lyme disease is also responsive to antibiotic treatment. Therapy is based on the disease category. (Lyme disease in “Red Book: 2015 Report of the Committee on Infectious Diseases,” [Elk Grove Village, Ill.: American Academy of Pediatrics, 2015, pp. 516-25]).

STARI clinically presents with a lesion that resembles erythema migrans in southern and southeastern states. However, it has not been associated with any of the complications reported with disseminated Lyme disease. Treatment is not recommended.

Tularemia and babesiosis are both responsive to antimicrobial therapy and would best be managed in consultation with an infectious disease physician.

A handy, concise, up to date reference guide about all of the tick-borne diseases including photographs is available at the App Store. The Tickborne Diseases App was developed by the CDC and it is free!

Prevention

The cornerstone of disease prevention is avoidance of mosquito and tick bites, in addition to eliminating mosquito breeding sites. Ticks are generally found near the ground, in brushy or wooded areas. They usually wait for a potential host to brush against them. When this happens, they climb onto the host and find a site to attach.

Is there a role for antimicrobial prophylaxis once a tick has been discovered? There is no data to support antimicrobial prophylaxis to prevent Rocky Mountain spotted fever, ehrlichiosis, and anaplasmosis. Prophylaxis with doxycycline or ciprofloxacin is recommended for children and adults after exposure to an intentional release of tularemia and for laboratory workers after inadvertent exposure. For prevention of Lyme disease, a single dose of doxycycline (4 mg/kg, max dose 200 mg) may be offered under limited conditions: The patient is at least 8 years of age, resides in an area where Lyme is highly endemic, the tick removed was engorged, therapy can be initiated within 72 hours after tick removal, and the estimated time of attachment was at least 36 hours. There is inadequate data on the use of amoxicillin.

Remember, not all mosquitoes are alike. Those that transmit chikungunya, dengue, and Zika (Aedes mosquitoes) are primarily daytime mosquitoes, but also can bite at night. West Nile is transmitted by Culex mosquitoes, which feed from dusk to dawn.

Here are some tips to share with your patients that should decrease their chances of acquiring a mosquito or tick-borne disease:

• Apply mosquito repellent only to intact exposed skin when outdoors. Most repellents can be safely used on children at least 2 months of age and older. Avoid applying repellent directly on the child’s hand. Use at least a 20% DEET (N,N-diethyl-meta-toluamide) containing product. Other Environmental Protection Agency–registered repellents are an alternative (Additional information is available at http://www2.epa.gov/insect-repellents). Products containing oil of lemon eucalyptus (OLE) or p-Menthane-3,8-diol (PMD) should not be used on children under 3 years of age.

• Apply permethrin to clothing, hats, boots, and so on. It is designed to repel mosquitoes and ticks. It can last for several washings. It is ideal to spray over nets covering carriers in children younger than 2 months of age.

• Wear long-sleeved shirts and long pants tucked inside of socks when hiking.

• Check for ticks daily, especially under the arms, behind the ears, around the waist, behind the knees, and inside belly buttons after outdoor activities.

• Have your patients learn how to effectively remove a tick. With a fine tipped tweezer, grasp the tick as close to the skin as possible and pull straight up with even pressure. Do not twist or jerk the tick. Do not squash the tick. Place it in a bag and dispose of it. Clean the site after removal with alcohol, iodine, or soap and water.

• Encourage families to mosquito proof their home by using screens on windows and doors, and using air conditioning when available.

• Empty and scrub all items that contain water such as birdbaths, planters, or wading pools around the outside of the home at least weekly because mosquitoes lay eggs in or near free standing water.

• Dogs and cats should be treated for ticks as recommended by the veterinarian.

The impact of the ongoing Zika virus outbreak is uncertain. While it may have an impact on those planning international travel now and in the near future, several arboviral and vector-borne diseases currently exist in the United States. Encouraging our patients to practice interventions to prevent mosquito and tick bites now will also serve to protect them if Zika virus becomes established in the Aedes mosquitoes here in the future and/or if they have plans for international travel. For up to date information on Zika virus for yourself and your patients, visit www.cdc.gov/zika.

Bonnie M. Word, M.D., is a pediatric infectious disease specialist and director of the Houston Travel Medicine Clinic. She said she had no relevant financial disclosures. Email Dr. Word at pdnews@frontlinemedcom.com.