Most infections are caused by ticks in the nymphal stage, because they are very small and thus may feed for long periods of time undetected. Nymphal ticks are generally the size of a poppy seed and sometimes with a dark head and a translucent body. Or, the nymphal ticks can be darker. (The younger larval ticks are very rarely infected.) Although deer are the preferred hosts of adult deer ticks, and tick populations are much lower in the absence of deer, ticks generally do not acquire Borrelia from deer, instead they obtain them from infected small mammals such as the white-footed mouse, and occasionally birds. Areas where Lyme is common are expanding.Within the tick midgut, the Borrelias outer surface protein A (OspA) binds to the tick receptor for OspA, known as TROSPA. When the tick feeds, the Borrelia downregulates OspA and upregulates OspC, another surface protein. After the bacteria migrate from the midgut to the salivary glands, OspC binds to Salp15, a tick salivary protein that appears to have immunosuppressive effects that enhance infection. Successful infection of the mammalian host depends on bacterial expression of OspC.Tick bites often go unnoticed because of the small size of the tick in its nymphal stage, as well as tick secretions that prevent the host from feeling any itch or pain from the bite. However, transmission is quite rare, with only about 1.2 to 1.4 percent of recognized tick bites resulting in Lyme disease.
Hydrocodone/paracetamol (also known as hydrocodone/acetaminophen) is the combination of the pain medications hydrocodone and paracetamol (acetaminophen). It is used to treat moderate to severe pain. It is taken by mouth. Recreational use is common in the United States.Common side effects include dizziness, sleepiness, constipation, and vomiting. Serious side effects include addiction, decreased rate of breathing, low blood pressure, serotonin syndrome, severe allergic reactions, and liver failure. Use during pregnancy may harm the baby. Use with alcohol is not recommended. Hydrocodone works by binding to the mu-opioid receptor. How paracetamol works is unclear but may involve blocking the creation of prostaglandins.Hydrocodone/paracetamol was approved for medical use in the United States in 1982. In the United States, it is a schedule II controlled substance. In 2020, it was the sixteenth most commonly prescribed medication in the United States, with more than 30 million prescriptions. It is not available in the United Kingdom, though the combination codeine/paracetamol is. It is sold under the brand names Vicodin and Norco among others. Uses
Medical
Hydrocodone/paracetamol is a fixed-dose combination consisting of the opioid hydrocodone and the non-opioid analgesic paracetamol. It is indicated for relief of moderate to severe pain of acute, chronic, or postoperative types. Hydrocodone/paracetamol comes in oral solution and tablet formulations; however strength of each component may vary. In October 2014, the Drug Enforcement Administration rescheduled hydrocodone combination drugs from schedule III to schedule II due to its risk for misuse, abuse, and diversions. Recreational
Hydrocodone diversion and recreational use has escalated in recent years due to its opioid effects.