Neurotoxic shellfish poisoning (NSP) is caused by the consumption of brevetoxins, which are marine toxins produced by the dinoflagellate Karenia brevis (among several others). These toxins can produce a series of gastrointestinal and neurological effects. Outbreaks of NSP commonly take place following harmful algal bloom (HAB) events, commonly referred to as "Florida red tide" (given that blooms are more commonplace along the coasts of Florida and Texas, especially during late summer and early fall). Algal blooms are a naturally-occurring phenomenon, however their frequency has been increasing in recent decades at least in-part due to human activities, climate changes, and the eutrophication (over-abundance of plant nutrients as a result of agricultural runoff, deforestation, river bed erosion, etc.) of marine waters. HABs have been occurring for all of documented history, evidenced by the Native Americans understanding of the dangers of shellfish consumption during periods of marine bioluminescence (a phenomenon observed during algal blooms). Blooms have been noted to occur as far north as North Carolina and are commonly seen alongside the widespread death of fish and sea birds. In addition to the effects on human health, the economic impact of HAB-associated shellfish toxin outbreaks can have significant economic implications as well due to not only the associated healthcare costs, but the adverse impact on the commercial shellfish industry. Causes
Humans are typically exposed to these potent natural toxins via filter-feeding mollusks (i.e., shellfish), because shellfish accumulate biotoxins in their flesh due to the way that they feed.
A genital ulcer is an open sore located on the genital area, which includes the vulva, penis, perianal region, or anus. Genital ulcers are most commonly caused by infectious agents (fungal infections, secondary bacterial infections, or sexually transmitted diseases such as genital herpes, syphilis or chancroid). However, this is not always the case, as a genital ulcer may have noninfectious causes as well. Overview
A genital ulcer may be located on the vulva, penis, perianal region, or anus. Globally, the incidence of genital ulcers is estimated to be approximately 20 million cases annually. The most likely cause of a genital ulcer varies depending on the characteristics of a population and location. The most common cause of genital ulcers in the United States is herpes simplex infections, with syphilis the second most common cause, and chancroid the third. These common causes of genital ulcer disease (HSV-1, HSV-2 and treponema pallidum) can all be efficiently transmitted through oral sex.Important signs associated with genital ulcers that may assist in the diagnosis of the cause of the genital ulcer may include the presence of tender or non-tender enlarged lymph nodes in the groin area, a painful or non-painful genital ulcer, or the presence of vesicular lesions, which are small, painful, elevated blisters.The most common causes of a genital ulcer include infectious agents, with sexually transmitted diseases being the most common, but which can also include fungal infections and secondary bacterial infections.