August 23, 2023

Locally acquired mosquito-borne malaria has occurred in the United States in 2023 in Florida, Texas, and Maryland. Previously, the last locally reported malaria cases were in 2003 when eight cases of locally acquired malaria were identified in Palm Beach County, FL. Despite these recent cases, the risk of locally acquired malaria remains extremely low in the United States. Protect yourself by preventing mosquito bites, by taking appropriate preventive measures before traveling, and by knowing signs and symptoms of malaria.

What is malaria?

Malaria is a serious and sometimes fatal disease caused by a parasite that commonly infects Anopheles mosquitoes, which then feeds on humans (Figures 1 and 2). Five kinds of malaria parasites can infect humans: Plasmodium falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi.

Figure 1 – Malaria Transmission Cycle

Figure 2 – Anopheles Mosquito

Figure 3 – Plasmodium vivax parasite infection in human blood sample

Worldwide, more than 240 million cases of malaria occur each year (95% in Africa) (Map 1). Almost all cases of malaria in the U.S. are imported (travel-associated) and occur in people traveling from countries with malaria transmission, many from sub-Saharan Africa and South Asia. Prior to 2020, approximately 2,000 cases of mostly travel-related malaria were diagnosed in the U.S. each year; approximately 300 people experienced severe disease (most P. falciparum), and 5 to 10 people with malaria died yearly. Most imported cases of malaria in the U.S. are diagnosed during summer and early fall.

Map 1 – Malaria-Endemic Countries (CDC)

While Anopheles mosquito vectors are found throughout many regions of the country, they are only capable of transmitting malaria if they feed on a malaria-infected person. The risk is higher in areas where local climatic conditions allow the Anopheles mosquito to survive during most of the year or among people who travel to locations where malaria is endemic. Despite the recent malaria cases in Florida, Texas, and Maryland, the risk of locally acquired malaria in Pennsylvania remains extremely low.

Anyone can get malaria. Most cases occur in people who live in countries with malaria transmission, however, people from countries with no malaria can become infected when they travel to countries with malaria or through a blood transfusion (although this is very rare). Also, an infected mother can transmit malaria to her infant before or during delivery.

• Symptoms of malaria include:
• • Fever and flu-like illness including shaking chills, headache, muscle aches and tiredness.
  • Nausea, vomiting and diarrhea.
  • Anemia and jaundice (yellow coloring of the skin and eyes) because of the loss of red blood cells.

How can you protect yourself?

If you will be traveling outside the United States:

• Obtain a detailed itinerary including all possible destinations that may be encountered during the trip and check to see if malaria transmission occurs in these locations.
• Visit your health care provider 4-6 weeks before foreign travel for any necessary vaccinations, as well as a prescription for an antimalarial drug, if needed.
• If prescribed, take your antimalarial drug exactly on schedule without missing doses.
• Sleep under a mosquito bed net (preferably one that has been treated with insecticide).
• Purchase all the medications that you need before you leave the United States. As a precaution, note the name of the medication(s) and the name of the manufacturer(s). That way, in case of accidental loss, you can replace the drug(s) abroad at a reliable vendor.

To prevent malaria and mosquito bites:

• Use EPA approved insect repellent.
• Wear long-sleeved shirts and long pants to cover your skin from mosquito bites.
• Treat your clothing and gear with an insecticide.
• Prevent mosquito bites when traveling: Sleep under a mosquito net if you are outside or when screened rooms are not available (DO NOT sleep directly against the net, as mosquitoes can still bite through holes in the net).
• Take steps to control mosquitoes indoors and outdoors:
• Maintain good screens on windows and doors to keep infected mosquitoes out.
• Regularly empty any outside containers, or drill drainage holes in their bottoms.
• Turn over plastic wading pools and wheelbarrows when not in use.
• Clean clogged roof gutters that may allow the pooling of rainwater.
• Do not allow water to stagnate in bird baths or ornamental ponds.
• Clean and chlorinate swimming pools and remove standing water from pool covers.
• Use landscaping to eliminate standing water that routinely collects on your property.
• Remove discarded tires from your property as they provide habitat for larva when they fill with water.
• Use Bacillus thuringiensis israelensis (Bti) tablets for standing water that can't be eliminated.  These tablets are available at any lawn and garden store and will kill any mosquito larvae present, but the water will remain safe for people, pets, aquatic life, and plants.

If you or a family member might have Malaria

• Contact your health care provider immediately and provide your travel history
  

RESOURCES FOR MORE INFORMATION

• PA DOH Vectorborne Disease webpage: Vectorborne Diseases
• DEP mosquito surveillance website: https://www.dep.pa.gov/Business/ProgramIntegration/Vector-Management/Mosquitoes/Pages/default.aspx

This update provides general information. Please contact your physician for specific clinical information.
 
If you have any questions, contact us at 1-877-PA-HEALTH.

August 9, 2023

 On June 6, the first Jamestown Canyon virus (JCV) positive mosquito pools were collected in Pennsylvania in Lackawanna and Luzerne counties by the Pennsylvania Department of Environmental Protection mosquito surveillance program. These results were confirmed by the Centers for Disease Control and Prevention (CDC). Since testing mosquito pools for JCV began in 2022, these are the first in Pennsylvania to be identified. The first mosquito positive pools indicate JCV is circulating in Pennsylvania and infection in residents is possible.

What is JCV?

JCV is spread to people by infected mosquitoes. JCV can be spread by many types of mosquitoes, depending on location and time of year. Mosquitoes become infected when they feed on deer or other animals that have the virus in their blood. Infected mosquitoes can then spread the virus to people and other animals by biting them (Figure 1.)

Figure 1 – Jamestown Canyon Virus Transmission Cycle

The virus is found throughout much of the United States, but most cases are historically reported from the upper Midwest (Map 1). Cases occur from late spring through mid-fall.  In the United States, an average of 17 Jamestown Canyon virus neuroinvasive disease cases are reported each year (Figure 2). The Pennsylvania Department of Health reported one JCV human illness in the state in 2013.

Map 1 – JCV human disease cases reported by state of residence, 2011-2022, All diseases cases

Source: CDC ArboNET

Figure 2 – JCV Human disease cases in United States, 2011-2022

Source: CDC ArboNET

Many people infected with JCV do not have symptoms. For people with symptoms, the time from mosquito bite to feeling sick (incubation period) ranges from a few days to 2 weeks.

• Initial symptoms can include fever, fatigue, and headache.
• • Some people also have respiratory symptoms such as cough, sore throat, or runny nose.
• Jamestown Canyon virus can cause severe disease, including infection of the brain (encephalitis) or the membranes around the brain and spinal cord (meningitis).
• • Symptoms of severe disease can include stiff neck, confusion, loss of coordination, difficulty speaking, or seizures.
  • About half of patients reported with symptomatic JCV disease are hospitalized.
  • Deaths associated with JCV infection are rare.

 
How can you protect yourself?

To prevent JCV and mosquito bites:

• Use EPA approved insect repellent.
• Wear long-sleeved shirts and long pants to cover your skin from mosquito bites.
• Treat your clothing and gear with an insecticide.
• Take steps to control mosquitoes indoors and outdoors by:
• Maintaining good screens on windows and doors to keep infected mosquitoes out.
• Regularly emptying any outside containers, or drilling drainage holes in their bottoms.
• Turning over plastic wading pools and wheelbarrows when not in use.
• Cleaning clogged roof gutters that may allow the pooling of rainwater.
• Not allowing water to stagnate in bird baths or ornamental ponds.
• Cleaning and chlorinating swimming pools and removing standing water from pool covers.
• Using landscaping to eliminate standing water that routinely collects on your property.
• Removing discarded tires from your property as they provide habitat for larva when they fill with water.
• Using Bacillus thuringiensis israelensis (Bti) tablets for standing water that can't be eliminated, available at any lawn and garden store. The bacteria will infect and kill any mosquito larvae present, but the water will remain safe for people, pets, aquatic life, and plants.

If you or a family member might have JCV:

• Talk with your health care provider immediately
  

RESOURCES FOR MORE INFORMATION

PA DOH Vectorborne Disease webpage: Vectorborne Diseases
CDC JCV website:  Jamestown Canyon Virus | Jamestown Canyon virus | CDC
This fact sheet provides general information. Please contact your physician for specific clinical information.
 

If you have any questions, contact us at 1-877-PA-HEALTH.

November 10, 2022

Anaplasmosis is a tickborne disease, transmitted by the Ixodes scapularis tick or deer tick. Anaplasmosis is caused by the bacteria Anaplasma phagocytophilum. This is the same tick that transmits the bacteria that causes Lyme disease. Deer ticks are the most common ticks in Pennsylvania and ticks infected with A. phagocytophilum have been found in most counties in Pennsylvania. Overall, about 6% of nymphal deer ticks carry A.phagocytophilum and about 12% of adult ticks carry the bacteria. Nymphal deer ticks are active from May through July in Pennsylvania. Nymphal deer ticks are tiny, about the size of a poppy seed, and can be difficult to see. Adult deer ticks are most active in the fall but can be out in the winter when the temperatures are mild and in the spring. Adult deer ticks are larger, about the size of a sesame seed, and are usually easier to see.

Although anaplasmosis can affect persons of all ages, older adults tend to have the most severe symptoms. Early symptoms are generally non-specific and may include fever, chills, headache, malaise, myalgia, and sometimes gastrointestinal symptoms. Bloodwork may show anemia, thrombocytopenia, leukopenia, and elevated hepatic transaminases. If untreated, symptoms may progress to renal failure, peripheral neuropathies, DIC, rhabdomyolysis and hemorrhage.

Anaplasmosis cases have increased statewide in the last ten years. (Figure 1) Anaplasmosis has traditionally been highest in Pennsylvania's eastern counties. In recent years, cases have increased in the central Pennsylvania counties and now in western Pennsylvania counties. (Maps 1 and 2) Many persons in western Pennsylvania are not aware of the risks of anaplasmosis and may not take appropriate precautions and diagnoses may take longer.

Since adult deer ticks feed in the fall, people spending time outdoors may be at risk of acquiring tickborne illnesses, including anaplasmosis, in the cooler fall months. Although most people report anaplasmosis symptom onset in the summer when nymphal deer ticks are abundant, a second smaller peak occurs in the fall when adult deer ticks are feeding. (Figure 2) We urge Pennsylvanians to continue to be vigilant in preventing tick bites and tickborne diseases.

Figure 1 - Anaplasmosis Cases in Pennsylvania by Year, 2012-2021

Map 1 – Anaplasmosis Cases by County in Pennsylvania, 2012

Map 2 – Anaplasmosis Cases by County in Pennsylvania, 2021

Figure 2 – Anaplasmosis Case Onset by Month, 2012-2021

Additional resources:

• Vectorborne Disease Information for Healthcare Providers
• Tickborne Disease Information including Prevention and Education Materials
• Anaplasmosis Fact Sheet
• Anaplasmosis Q&A for Healthcare Providers
• Tick Prevention Information