Archive for the ‘mosquitoes’ Category

Patterns, Drivers, and Challenges of Vector-Borne Disease Emergence

https://www.liebertpub.com/doi/10.1089/vbz.2018.2432

Vector-Borne and Zoonotic DiseasesAhead of Print

Patterns, Drivers, and Challenges of Vector-Borne Disease Emergence

Andrea Swei, lisa I. Couper, Lark L. Coffey, Durrell Kapan, and Shannon Bennett

Published Online:https://doi.org/10.1089/vbz.2018.2432

Vector-borne diseases are emerging at an increasing rate and comprise a disproportionate share of all emerging infectious diseases. Yet, the key ecological and evolutionary dimensions of vector-borne disease that facilitate their emergence have not been thoroughly explored. This study reviews and synthesizes the existing literature to explore global patterns of emerging vector-borne zoonotic diseases (VBZDs) under changing global conditions. We find that the vast majority of emerging VBZDs are transmitted by ticks (Ixodidae) and mosquitoes (Culicidae) and the pathogens transmitted are dominated by Rickettsiaceae bacteria and RNA viruses (Flaviviridae, Bunyaviridae, and Togaviridae). The most common potential driver of these emerging zoonoses is land use change, but for many diseases, the driver is unknown, revealing a critical research gap. While most reported VBZDs are emerging in the northern latitudes, after correcting for sampling bias, Africa is clearly a region with the greatest share of emerging VBZD. We highlight critical gaps in our understanding of VBZD emergence and emphasize the importance of interdisciplinary research and consideration of deeper evolutionary processes to improve our capacity for anticipating where and how such diseases have and will continue to emerge.

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**Comment**

Regarding ticks, it’s birds that are doing the damage:  https://madisonarealymesupportgroup.com/2017/08/17/of-birds-and-ticks/

Excerpt:

But birds facilitate the spread of ticks, picking them up in Maryland, Connecticut and other eastern states as they fly north in the spring, Lubelczyk explained.

“As they’re migrating, they’re either dropping the ticks off as they fly or when they land. They’re kind of seeding them along migration patterns.

https://madisonarealymesupportgroup.com/2016/10/02/the-role-of-birds-in-tickborne-illness/

Excerpt:

Birds play a central role in the ecology of tick-borne pathogens. They expand tick populations and pathogens across vast distances and serve as reservoirs that maintain and amplify transmission locally.

 

Malaria Hides In People Without Symptoms

https://researchblog.duke.edu/2019/11/11/malaria-hides-in-people-without-symptoms/?

Malaria Hides In People Without Symptoms

It seems like the never-ending battle against Malaria just keeps getting tougher. In regions where Malaria is hyper-prevalent, anti-mosquito measures can only work so well due to the reservoir that has built up of infected humans who do not even know they carry the infection.

In high-transmission areas, asymptomatic malaria is more prevalent than symptomatic malaria. Twenty-four percent of the people in sub-Saharan Africa are estimated to harbor an asymptomatic infection, including 38 to 50 percent of the school-aged children in western Kenya. Out of the 219 million malaria cases in 2017 worldwide, over 90%  were in sub-Saharan Africa….(See link for full article)

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**Comment**

I post this because Malaria is a protozoan similar to Babesia.  The question begging to be asked is, “Can people also have an asymptomatic Babesia infection that lies around for an opportune time to emerge?”

My educated guess is yes, it can.

Key quote:  “P. falciparum malaria is very diverse in the region,” she said. “It’s constantly mutating, which is why it’s so hard to treat….many study participants were infected with multiple, genetically-distinct malaria infections. Some carried up to fourteen strains of the parasite.

For more:  https://madisonarealymesupportgroup.com/category/babesia-treatment/

https://madisonarealymesupportgroup.com/2018/10/11/babesia-found-in-patient-with-persistent-symptoms-following-lyme-treatment/

https://madisonarealymesupportgroup.com/2019/09/05/babesia-subverts-adaptive-immunity-and-enhances-lyme-disease-severity/

We show that

  • burgdorferi infection attenuates parasitemia in mice while
  • B. microti subverts the splenic immune response, such that a marked decrease in splenic B and T cells, reduction in antibody levels and diminished functional humoral immunity, as determined by spirochete opsonophagocytosis, are observed in co-infected mice compared to only B. burgdorferi infected mice

Furthermore

  • immunosuppression by B. microti in coinfected mice showed an association with enhanced Lyme disease manifestations.
Due to the high prevalence of infection and the issues of congenital transmission and transmission through blood transfusion, the issue of concurrent infection and what it does to animal and human health is of paramount importance.

Assessing the Landscape of Eastern Equine Encephalitis Prevention & Treatment

https://www.contagionlive.com/news/assessing-the-landscape-of-eastern-equine-encephalitis-prevention-and-treatment

Assessing the Landscape of Eastern Equine Encephalitis Prevention and Treatment

NOV 25, 2019 | MICHAELA FLEMING

The first case in the 2019 season was confirmed in August in Massachusetts. As of November 12, there have been 36 cases of the illness reported across 8 states. This is a sharp contrast to the 6 cases confirmed in 2018. More worrisome, one-third of the cases confirmed in 2019 have been fatal.Now, experts from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health have published a commentary in The New England Journal of Medicine describing the EEE virus along with research and development that is needed to address the growing threat of the virus and other vector-borne conditions.

The virus is typically spread between Culiseta melanura mosquitoes and birds that live in wetlands; however, other mosquito species can transmit the virus to humans and mammals. In the event of human infection, it takes approximately 3 to 10 days for symptoms to present.

Initial signs and symptoms include fever, muscle aches, nausea, and headache. Infection may progress to neurological EEE are “nonspecific” but progress rapidly and can be permanent. However, the authors of the report noted that 96% of individuals infected with EEE virus do not develop symptoms. Furthermore, specific diagnostic testing may not reveal the infection as the virus is difficult to isolate from clinical samples.

“Although point-of-care diagnostics for EEE and many other mosquito-borne causes of encephalitis are not available, currently they would be of limited value in the absence of effective treatment,” the authors of the report write.

Currently, there are no available antiviral drugs or vaccines that are safe and effective against EEE. At this point in time, patients with EEE are treated with supportive care including intensive care and ventilator assistance. Social support and counseling are recommended for the patient and their family members due to the serious, and sometimes long-term, effects of the infection.

According to NIAID’s statement, many compounds and candidates are currently in development. The authors note that monoclonal antibodies have demonstrated efficacy when given prior to infection in an animal model.

While there are several EEE vaccine candidates in development, the authors caution that these candidates may struggle to reach advance development and licensure. Vaccines that are mosquito-saliva based which are in development to protect against multiple mosquito-borne diseases are in early stages.

Moreover, due to the rare nature of the outbreaks which occur sporadically in unpredictable locations for short periods of time it is difficult to identify an appropriate target population for vaccination.

“In the absence of effective EEE vaccines and treatments, state and local health departments can provide an early warning of imminent human infections by surveilling horses, birds and mosquitoes, but these efforts are threatened by insufficient funding,” the authors said in the press release.

Despite the challenges to developing vaccines and treatments for EEE, the authors of the report caution that simply ignoring the virus would be irresponsible. While EEE outbreaks have been infrequent, a number of emerging and re-emerging mosquito-borne diseases such as dengue, West Nile, Zika, and chikungunya have been documented in the Americas in recent years.

“The spike in cases in 2019 and the looming presence of other, potentially deadly arboviruses in the United States and globally demand a national defense strategy for arboviruses and other vector-borne diseases,” the authors conclude.

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Another detail to highlight is that the CDC does not mention these blood-sucking insects as a possible transmitter of Lyme borreliosis, which, although being low in the percentage shown in the studies, could be a factor in the spread of this disease by the world.

Deadly Mosquito-borne Virus That Causes Brain Swelling in Humans Found in Florida

https://www.cnn.com/2019/07/28/health/eastern-equine-encephalitis-mosquito-outbreak-chickens-florida-trnd/index.html

A deadly mosquito-borne virus that causes brain swelling in humans has been detected in Florida

(CNN) Florida health officials are warning of an uptick in a mosquito-borne virus known as Eastern equine encephalitis (EEE).
Several sentinel chickens tested positive for EEE, which can spread to humans via infected mosquitoes and cause brain infection and swelling, the Florida Department of Health in Orange County said in a Thursday statement. Sentinel chickens are fowl that are tested regularly for the West Nile virus and EEE. Their blood can show the presence of the diseases, but they don’t suffer from the effects of the viruses.
Following the positive tests for the sentinel chickens in Orange County, the health department said “the risk of transmission to humans has increased.”
Only about seven cases of the EEE virus in humans are reported in the US each year, the Centers for Disease Control and Prevention says.
However, the disease can be fatal: about 30% of people who contract it die, according to the CDC. Many survivors have ongoing neurologic problems.
People develop symptoms about 4 to 10 days after they are bitten by an infected mosquito, the CDC says. Signs include sudden onset of headache, high fever, chills and vomiting. More severe symptoms include disorientation, seizures and coma.
With summer in full swing, mosquitoes are buzzing around at peak populations. Officials warned people to avoid being bitten by draining standing water around their homes, covering skin with clothing or repellant, and using screens to cover doors and windows.
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New Hampshire Man Tests Positive For Jamestown Canyon & Powassan Viruses

http://indepthnh.org/2019/08/08/dhhs-kingston-man-tests-positive-for-rare-viruses-carried-by-ticks-mosquitoes/

DHHS: Kingston Man Tests Positive for Rare Viruses Carried By Ticks, Mosquitoes

Public Domain photo

NH health officials say protect yourself from mosquito bites.
Concord, NH – The New Hampshire Department of Health and Human Services (DHHS) announced that an adult from Kingston, NH tested positive for both Jamestown Canyon virus (JCV) and Powassan virus (POW), the first time these vector-borne diseases have been identified in the State in 2019.JCV is transmitted by infected mosquitoes and POW is transmitted by infected ticks. There are no vaccines to prevent JCV or POW and treatment consists of supportive care.

“From spring until fall, New Hampshire residents and visitors are at risk for a number of different infections from the bite of mosquitoes and ticks, and this case highlights the risk from both,” said Dr. Benjamin Chan, State Epidemiologist.

“In addition to Jamestown Canyon virus and Powassan virus, there are a number of other viral and bacterial infections that can be transmitted by mosquitoes and ticks in New Hampshire, and we recommend that residents and visitors continue to take basic steps to prevent mosquito and tick bites in order to stay healthy.”

Jamestown Canyon virus is a mosquito-borne pathogen that circulates widely in North America primarily between deer and a variety of mosquito species, but it can also infect humans. First reported in the early 1970s, reports in humans are rare but have been increasing over the last several years. This is New Hampshire’s seventh case of JCV since the first report of the disease in 2013. Most reported illnesses caused by JCV have been mild, but moderate-to-severe central nervous system involvement has been reported.

Powassan virus infection is similar to mosquito-borne viruses like JCV, West Nile virus (WNV), and Eastern equine encephalitis (EEE), but is transmitted to people by infected ticks. POW was identified as a cause of human illness in the late 1950’s. In the last decade, 144 cases of POW have been detected in the United States. This is New Hampshire’s fourth case of POW, also since 2013. In New Hampshire, the blacklegged tick is the most likely to transmit this virus to people. A tick needs to be attached to a person for only 15 minutes to transmit POW. Some people who are infected may experience mild illness or no symptoms. Powassan virus can also infect the central nervous system causing brain inflammation, which may be disabling or fatal.

The Kingston resident had no recent history of travel outside our state and spent a great amount of time outdoors. Residents and visitors to New Hampshire should protect themselves and their family members by:

·         using an effective mosquito and tick repellant containing DEET (20-30%), Picaridin, or oil of lemon eucalyptus

·         wearing protective clothing, tucking shirts into pants and pants into socks

·         removing standing water from around your house so mosquitoes do not have a place to breed

·         being mindful of tick habitat keeping grass cut short, and

·         performing frequent and daily tick checks with immediate tick removal.

Vitamin B, ultrasonic devices, incense, and bug zappers have not been shown to be effective in preventing mosquito- or tick-borne diseases.

Other mosquito- and tick-borne illnesses that have been documented in New Hampshire include WNV and EEE from mosquitoes, and Lyme disease, anaplasmosis, babesiosis, and Borrelia miyamotoi from ticks. Biting mosquitoes will continue to be a disease concern until there are two, statewide, hard frosts. Risk of tick bites exists when temperatures are above freezing and ticks are not covered by snow.

People can be infected and not develop any symptoms, or only develop very mild symptoms. Early symptoms can include flu-like illness including fever, muscle aches, headaches, and fatigue. People infected with JCV, EEE, WNV, and Powassan can develop more serious central nervous system disease, including meningitis or encephalitis. If you or someone you know is experiencing flu-like symptoms, including fever and headache, contact your local medical provider.

Anyone with questions about vector-borne illnesses can call the DHHS Division of Public Health Services Bureau of Infectious Disease Control at (603) 271-4496 between 8 AM to 4:30 PM, Monday through Friday. More information can also be found online at www.dhhs.nh.gov and www.cdc.gov.

News story here:  https://www.wmur.com/article/new-hampshire-adult-infected-with-jamestown-canyon-virus-powassan-virus/28647142

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**Comment**

Pathogens have a certain proclivity for their vectors. It’s always interesting to me to entertain the possibility that perhaps there is cross over.

For instance, borrelia has been found in mosquitoes and many patients claim to have become infected with Lyme after a mosquito bite:

https://madisonarealymesupportgroup.com/2018/11/07/are-mosquitoes-transmitting-lyme-disease/

https://www.ncbi.nlm.nih.gov/m/pubmed/26631488/  Excerpt:

…results show that DNA of Borrelia afzelii, Borrelia bavariensis and Borrelia garinii could be detected in ten Culicidae species comprising four distinct genera (Aedes, Culiseta, Culex, and Ochlerotatus). Positive samples also include adult specimens raised in the laboratory from wild-caught larvae indicating that transstadial and/or transovarial transmission might occur within a given mosquito population.

BTW: THE LAST STUDY ON THE POTENTIAL OF OTHER BUGS TRANSMITTING LYME (MINUS THE GERMAN STUDY ON MOSQUITOS) WAS DONE OVER 30 YEARS AGO.  AND, WHILE NO SPIROCHETES WERE ISOLATED FROM THE HAMSTERS, ANTIBODIES WERE FOUND – EVEN BACK THEN.

Therein lies the hang up. The presence of antibodies does not prove infection. It’s interesting that the current CDC 2-tiered testing relies upon antibodies…..

The transmission of Bartonella from ticks is also still being quibbled about with some just stating emphatically that it is:  https://madisonarealymesupportgroup.com/2016/01/03/bartonella-treatment/ while others take a more conservative approach and say the science isn’t settled: https://madisonarealymesupportgroup.com/2019/07/13/suspected-insect-and-arthropod-vectors-for-bartonella-species-galaxy/

This issue of what is being transmitted by whom seems to me to be a very important and practical issue.  Why isn’t the science being done?

Also, while the media continues to inform us all of this is “rare,” please remember that many of these pathogens are not mandatorily reported, and we have no idea on prevalence. Coppe Lab out of Wisconsin emphatically states Powassan is NOT rare:

http://www.coppelabs.com/blog/why-is-powassan-virus-infection-still-described-as-rare-and-mysterious/  Please read the following excerpt by Coppe Lab here in Wisconsin,

For the last two years, Coppe Laboratories has dedicated a significant amount of time and resources to dispelling the myth that infection with Powassan virus, a virus transmitted by tick bite, is rare. The Centers for Disease Prevention and Control (CDC) reports only 100 cases of Powassan virus infection in the United States in the last 10 years. Indeed, that statistic gives the illusion that Powassan infection is rare. However, did you know that the only infections reported to CDC are those that are life-threatening, particularly cases causing severe inflammation of the brain like the case reported in LiveScience? Coppe has published three new papers in the last year that clearly show Powassan virus infection is not rare are at all,and until testing for this virus is included as part of tick-borne disease screening panels infections will continue to be underreported. Coppe’s Powassan Guide, which can be downloaded from the website, summarizes the findings from both tick and human Powassan prevalence studies, as well as defining the patient populations that would benefit most from Powassan testing.

To my knowledge, not only are there few current studies on what transmits what, but nothing has been done  on transmission time when multiple pathogens are being transmitted concurrently. Everyone’s stuck on climate change….