Mosquitoes in the Fall

 

Summer is coming to and end.  What does that mean?  It means no more vacations to the beach, the kids are starting a new and exciting school year. The hot and humid weather is coming to and end. Some people look forward to the end of summer because they’re eager to say goodbye to mosquitoes. Unfortunately, mosquitoes don’t disappear with the hot summer temps.  What do they do?

They thrive in cooler weather. Mosquitoes can be just as active as in the summer. Since they are cold-blooded, they do hibernate or die off, but only once temperatures are consistently below 50°F. So, in the early fall months, they feel right at home in the cool, but not cold, weather. The cooler temperatures that most of us look forward to, also mean mosquitoes are more active during the day, instead of in the evening.

The mosquito spends the fall preparing for winter. Certain species lay winter-hardy eggs that can survive the cold and then hatch when Spring comes with warmer temperatures and rain. The females of other species mate, fatten up, and go into hibernation in protected places, such as in a log or under a house. When the weather warms up in the spring, the female emerges and lays eggs. Very cold temperatures signal the end of the biting. Some mosquitoes may be able to survive the winter, but they certainly won’t be out biting you once the temperatures drops. The first frost is typically the time when you can say goodbye to those buzzing pests.

 

ZIKA

Zika ‘Replicates and Persists’ in Fetal Brain, Placenta Study strengthens tie to microcephaly Zika virus RNA was found in both fetal brain and placental tissue of Zika-related pregnancy losses and infants born with microcephaly, indicating the virus continues to replicate in a fetus months after a mother’s initial infection, and even after birth, researchers reported.

Examining infant brain tissue, relative levels of Zika RNA were over 1,000-fold higher than those found in second trimester, third trimester, or fullterm placentas. In placental tissue, relative levels of Zika RNA in first trimester placentas were 25- fold higher than in second trimester, third trimester, or full-term placentas, reported Julu Bhatnagar, PhD, of the CDC in Atlanta, and colleagues.

There was a mean 163 days in between the time of maternal symptom onset and detection of Zika virus RNA in brain tissue, and a mean 81 days to detection in placental tissue, they wrote in Emerging Infectious Diseases.

“These findings demonstrate that Zika virus replicates and persists in fetal brains and placentas, providing direct evidence of its association with microcephaly,” the authors concluded.

“We don’t know how long the virus can persist, but its persistence could have implications for babies born with microcephaly and for apparently healthy infants whose mothers had Zika during their pregnancies,” Bhatnagar said in a statement. “More studies are needed to fully understand how the virus can affect babies.

” The authors stated that Zika virus antigens were previously detected in human and neonatal brains and the placentas of pregnant women, but “the presence of antigens does not necessarily indicate virus replication,” they wrote.

They examined tissue samples from 52 patients with suspected Zika infection, including eight infants who died from microcephaly. They also looked at 44 placental tissue samples — 22 from women with adverse pregnancy outcomes and 22 from women whose pregnancy outcomes were normal.

Overall, 32 of 52 case patients had fetal brain and placental tissue that tested positive for Zika via reverse transcription polymerase chain reaction (RT-PCR) assays. There were also 24 of 32 patients testing positive for Zika, who reported “adverse pregnancy or birth outcomes.” Of these, 23 reported onset of symptoms in the first trimester.

There were 13 infants born with microcephaly — eight who died within a few minutes to 2 months after birth, and five infants born with microcephaly who lived. While brain tissues of these eight infants tested positive for Zika, tests for kidney, liver, spleen, heart, and rib were negative for the virus.

Mothers of these eight infants all reported symptom onset during the first trimester, but 21 of 22 case patients — including eight who tested positive for Zika — who delivered apparently healthy infants reported symptom onset during the second or third trimester. This added to similar research that found the virus is most deadly to the fetus early in pregnancy.

The authors also shed additional light on the mechanism of fetal infection by performing in situ hybridization, which can help identify specific DNA or RNA sequences. In this case, they found Zika virus in tissues of 32 case patients who tested positive for Zika. They also found viral activity in the Hofbauer cells of the placenta, which are involved in preventing the transmission of pathogens from mother to fetus, as well as in neural cells and neurons.

“Our findings indicate that Hofbauer cells may play a role in the dissemination or transfer of Zika virus to the fetal brain, particularly during early pregnancy,” they wrote.

The authors cited their Zika tissue-based PCR testing as a critical method of establishing a retrospective diagnosis of Zika virus.

Michigan Mosquito Control Association P.O. Box 366 Bay City, MI 48707

Unmasking the Many Myths About Mosquitoes

Ask any vertebrate if it’s fond of mosquitoes, and you’ll get an emphatic, “Are you crazy?!” in response. But, of all the vertebrates out there, only humans have the scoop on the facts and fiction regarding the pesky little vermin and their capacity to spread disease. Or so you would think. Unfortunately, some humans have fallen prey to some misinformation which we aim to correct.

Myth: All mosquitoes bite.
Fact 1: Only Mrs. Mosquito bites. Mr. Mosquito is cool simply buzzing around your head chasing after his honey bunch. Not even all of the girls sidle up to the dinner table that is your skin, either.
Fact 2: Out of more than 3,500 species, a few can actually lay eggs without a blood meal first. But the biters far outnumber the peaceful ones making it seem like every species is out to get you.

Myth: Mosquitoes can spread HIV.
Fact: Mama Mosquito can deliver malaria, West Nile Virus, encephalitis, Zika virus, dengue fever, chikungunya and other nasties through her saliva as she drills you with her proboscis. However, she digests the HIV virus and eliminates it through the other end of her tract, by which time it is rendered harmless.

Myth: People with Type-O blood attract more mosquitoes.
Fact: Like Dracula, mosquitoes are happy to drink anyone’s blood. What draws them is your carbon dioxide emissions and body heat, plus maybe a cocktail of your skin’s genetically-determined fragrance. Perhaps the myth gained traction because Type-O is the most common blood type of all.

Myth: Citronella candles repel mosquitoes.
Fact: Who started that myth? The guy who invented citronella candles? The truth is, other botanicals effectively repel mosquitoes, but citronella fails to live up to claims.

Myth: Citizens of the United States are in very little danger from mosquito-borne diseases.
Fact: Americans enjoy no special favor in that department; however, as well-fed as Americans are, it’s possible that our immune systems have a heartier resistance once infected. But that’s mere speculation. We do know, though, that the U.S. definitely has infected mosquitoes and once in a while we get an outbreak of mosquito-borne disease.

Myth: Every continent on the planet has mosquitoes. You can’t escape them.
Fact: Yes, you can. But you’ll have to move to Antarctica to do it. Even the arctic tundra and Siberia swarm with the pests during their short summers.

Myth: My family will never enjoy the outdoors in the summer because of the difficulty in eradicating the mosquitoes in my yard and the exorbitant cost of pest control.
Fact: Sit up and smile! The Mosquito Squad can bring effective and affordable mosquito control to your life right now. If you can work with your neighbors, too, and eliminate all the breeding places mosquitoes love, you can go a long way towards thinning out the hoard. Plus, avoid the yard during the hours of dawn and dusk when the critters are out in force. After that, apply a personal repellent containing DEET so you’re set to enjoy your yard again. Let us take care of the mosquitoes. Call 269-932-1444

 

5 T’s – Tip, Toss, Turn, Tarps & Treat

Now that the snow is gone, its time to clean up the yard for the spring.   Keep this in mind to help reduce the mosquito population in your yard for the season.

 

Spring Is Here!

Zika Effects On Adults

Two studies released today detail Zika-related ear and eye problems while the US Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) updated their weekly Zika numbers.

“In a new study published in Clinical Infectious Diseases, Brazilian researchers detailed three cases of acute, transient hearing loss in adults who were infected with Zika virus. All patients were admitted to an ear, nose, and throat emergency department in the summer of 2015. One patient had laboratory-confirmed Zika, and the other two were probably infected with the flavivirus.

These are the first cases of acute hearing losses described during the current epidemic that began in Brazil.

The first patient was a 23-year-old man who was admitted to the hospital for hearing loss 2 weeks after suffering a fever, itching, and joint pain. The hearing loss lasted 4 days, and audiometry testing showed mild loss in the right ear. Blood tests confirmed Zika virus antibodies.

A 54-year-old woman also presented with moderate bilateral hearing loss 3 days after experiencing itching, dizziness, myalgia, and headache. Within 1 month her hearing issues were resolved, and lab tests showed she had both Zika and dengue antibodies.

The final patient was 58-year-old woman who had intense hearing loss and tinnitus for 2 days. Two weeks prior to hearing loss, she experienced itching, myalgia, dizziness, and headache. Her hearing returned after 3 weeks, and she had both dengue and Zika antibodies in her serum.

“This report of three cases indicates that transient hearing impairment may be a specific manifestation of acute ZIKAV disease,” the authors concluded.” A subsequent case-control study would be necessary to demonstrate this causal relationship and elucidate the mechanisms leading to auditory dysfunction in this setting.”

Another study, published today in The Lancet, described a case of bilateral posterior uveitis, or eye tissue inflammation, in a 26-year-old American man who was infected with Zika after traveling to Puerto Rico.

Two weeks after being diagnosed as having Zika virus with moderate symptoms, including red eyes, the man complained of seeing photopsias, or flashes of light. An eye exam showed mild ocular lesions, with symptoms resolving within 3 weeks.

The authors say this is the first description of Zika-related bilaterial posterior uveitis and acquired chorioretinal lesions.

Source: Center for Infectious Disease Research and Policy

Deer Ticks

NO TICKS—CALL 

Human cases of tick-borne Lyme disease on the rise in state

Sunday

Posted Feb 26, 2017 at 4:00 PM

DETROIT (AP) — Lyme disease cases have increased in Michigan due to the spread of blacklegged ticks in the state.

The ticks often carry the bacterium Borrelia burgdorferi with them, the Detroit Free Press reported.

The bacteria can transfer when they bite a human or animal and can cause Lyme disease, a serious infection that can be permanently debilitating when it’s not treated early and well.

There were less than 30 human cases of Lyme disease reported in Michigan in every year between 2000 and 2004, according to a recent study by Jean Tsao, an associate professor in Michigan State University’s departments of fisheries and wildlife and large animal clinical sciences. But the number had jumped to 90 reported cases by 2009, and by 2013, it was nearly 170 cases.

The Lyme disease spike in Michigan correlates with the spread of blacklegged ticks in the state.

In 1998, the ticks were established in only five counties and reported in more than 20 other counties. By 2016, the ticks were established in 24 Michigan counties and reported in 18 others.

Officials with the federal Centers for Disease Control and Prevention estimate the number of Lyme disease cases nationwide could be 10 times higher than what is reported.

Infected people and their doctors don’t often test for the disease because it’s relatively new in Michigan and its symptoms often mimic what feels like the flu. Erik Foster, an entomologist with the Michigan Department of Health and Human Services and co-author of the study, said doctors also don’t always report finding Lyme disease to their local public health department.

The genetics behind what mosquitos choose to bite

 

Mosquito-borne illnesses are a considerable burden on human and animal health, so understanding what influences the behavior of mosquitos could be useful. A recent study published in PLOS Genetics suggests that there may be a genetic component to mosquito behavioral preferences, including what they choose to bite.

The control of malaria depends on the propensity of mosquitos to bite humans versus other hosts—if mosquitos prefer humans, then they’re more likely to spread diseases between humans, but if they prefer to feed on other animals (like cows, for example), then mosquitos may not be contributing as significantly to the human burden of disease. Additionally, control of malaria depends on the tendency of mosquitos to rest in places where we can ensure they are likely to come into contact with insecticides. Mosquitos are more likely to encounter insecticides indoors, because homes in countries where malaria is endemic are more likely to have long-lasting, insecticide-treated nets, which will kill mosquitos if they come into contact with them. These nets are highly effective and have pared down the number of dangerous mosquito species in many parts of Africa.

For this PLOS study, some researchers were interested in investigating the potential that the surviving mosquitos may have adapted their behavior to avoid control measures like nets. And, if this were occurring through evolution, it should have left a mark in the pests’ genomes. So they investigated the genetic basis for mosquito host and resting area choices.

Researchers collected the mosquitos from villages in Africa, selecting specimens based on their primary hosts and resting areas. They selected some specimens that preferred to feed on cattle, others that preferred to feed on humans, as well as specimens that tended to rest either outdoors or indoors.

The scientists then sequenced the genomes of 23 human-feeding mosquitoes and 25 cattle-feeding mosquitos. They found a total of 4.8 million base-pair differences that they used to conduct the first genome-wide estimates of heritability for host choice and resting behavior. They used a principal component analysis to segregate individuals into three groups based on genomic variation. This uncovered a genetic component for host choice but did not find anything associated with indoor/outdoor resting behaviors.

In the researchers’ analysis, they found some compelling indications for a genetic component to host choice by using what’s called a chromosomal inversion analysis. A chromosomal inversion is a piece of chromosome that is flipped relative to its normal orientation. Chromosomal inversions do not necessarily cause abnormalities on their own, but they can be useful genetic markers. In this experiment, the researchers looked closely at two chromosome inversions known as 3Ra and 2Rb.

They used a novel inversion genotyping assay to detect a significant enrichment of the arrangement of 3Ra genetic inversion among cattle-fed mosquitos. Included in this inversion were two genes that coded for odorant signaling proteins and odorant receptors. The researchers think that these proteins may be linked to the preference for cattle over humans as a food source.

Though there are no immediate consequences to this finding, there are many ways in which this information could be used for future mosquito control measures. Perhaps targeted insecticidal approaches that alter the functioning of this odorant protein or receptor could be an effective future means of mosquito control. Or, alternatively, introducing lots of mosquitos with this genetic difference to the mosquito population could reduce the percentage of mosquitos that prefer to feed on humans. This paper is the first finding connecting a mosquito genetic variant with a specific behavioral pattern, and the finding opens the door to new potential control measures in the future.

PLOS, 2016. DOI: 10.1371/journal.pgen.1006303 (About DOIs).

Spring Is Just Around The Corner

 

Call Mosquito Squad for a love filled spring. Love should be in the air not Mosquitoes.