The presence of antibodies to the surface antigen, which are considered to be a marker of immunity, does not preclude reactivation. Treatment with prophylactic antiviral drugs can prevent the serious morbidity associated with HBV disease reactivation. Epidemiology
At least 296 million people, or 3.8% of the worlds population, had chronic HBV infection as of 2019. Another 1.5 million cases of acute HBV infection also occurred that year. Regional prevalences across the globe range from around 7.5% in Africa to 0.5% in the Americas.The primary method of HBV transmission and the prevalence of chronic HBV infection in specific regions often correspond with one another. In populations where HBV infection rates are 8% or higher, which are classified as high prevalence, vertical transmission (usually occurring during birth) is most common, though rates of early childhood transmission can also be significant among these populations. In 2021, 19 African countries had infection rates ranging between 8-19%, placing them in the high prevalence category.In moderate prevalence areas where 2–7% of the population is chronically infected, the disease is predominantly spread horizontally, often among children, or vertically. China’s HBV infection rate is at the higher end of the moderate prevalence classification with an infection rate of 6.89% as of 2019. HBV prevalence in India is also moderate, with studies placing India’s infection rate between 2-4%.Countries with low HBV prevalence include Australia (0.9%), those in the WHO European Region (which average 1.5%), and most countries in North and South America (which average 0.28%).
They most often involve the frontal and parietal lobes of the brain.Movement disorders can be found in a small percentage of individuals with neurosyphilis. The abnormal movements already reported were tremor, chorea, parkinsonism, ataxia, myoclonus, dystonia, athetosis, and ballism. Neuropsychiatric
Although neurosyphilis is a neurological disease, neuropsychiatric symptoms might appear due to overall damage to the brain. These symptoms can make the diagnosis more difficult and can include symptoms of dementia, mania, psychosis, depression, and delirium:These symptoms are not always present, and when they are, they usually appear in more advanced stages of the disease. Complications
The Jarisch-Herxheimer reaction is an immune-mediated response to syphilis therapy occurring within 2–24 hours. The exact mechanisms of reaction are unclear, however most likely caused by proinflammatory treponemal lipoproteins that are released from dead and dying organisms following antibiotic treatment. It is typically characterized by fever, headache, myalgia and possibly intensification of skin rash. It most often occurs in early-stage syphilis (up to 50%–75% of patients with primary and secondary syphilis). It is usually self-limiting and managed with antipyretics and nonsteroidal anti-inflammatory medications. Risk factors
There are several risk factors: high-risk sexual behavior from unprotected sex and multiple sexual partners. The HIV infection antiretroviral therapy (ART) suppresses HIV transmission, but not syphilis transmission. It may also be associated with recreational drug use. Pathophysiology
The pathogenesis is not fully known, in part due to fact that the organism is not easily cultured. Within days to weeks after initial infection, Treponema pallidum disseminates via blood and lymphatics.