Epidemiology
Because T. pallidum pertenue is temperature- and humidity-dependent, yaws is found in humid tropical forest regions in South America, Africa, Asia and Oceania.About three quarters of people affected are children under 15 years of age, with the greatest incidence in children 6–10 years old. Therefore, children are the main reservoir of infection.It is more common in remote areas, where access to treatment is poorer. It is associated with poverty and poor sanitation facilities and personal hygiene.Worldwide, almost 85% of yaws cases are in Ghana, Papua New Guinea, and the Solomon Islands. Rates in sub-Saharan Africa are low, but tend to be concentrated in specific populations. As of 2015, it is estimated that about 89 million people live in yaws-endemic areas, but data are poor, and this is likely an over-estimate.In the early 1900s, yaws was very common; in sub-saharan Africa, it was more frequently treated than malaria, sometimes making up more than half of treatments.Mass treatment campaigns in the 1950s reduced the worldwide prevalence from 50 to 150 million to fewer than 2.5 million; however, during the 1970s there were outbreaks in South-East Asia, and there have been continued sporadic cases in South America. As of 2011, it was unclear how many people worldwide were currently infected.From 2008 to 2012, 13 countries reported over 300,000 new cases to the WHO. There was no system for certifying local elimination of yaws, and it is not known whether the lack of reports from some countries is because they stopped having yaws cases or because they stopped reporting them.
Hypopnea is overly shallow breathing or an abnormally low respiratory rate. Hypopnea is defined by some to be less severe than apnea (the complete cessation of breathing), while other researchers have discovered hypopnea to have a "similar if not indistinguishable impact" on the negative outcomes of sleep breathing disorders. In sleep clinics, obstructive sleep apnea syndrome or obstructive sleep apnea–hypopnea syndrome is normally diagnosed based on the frequent presence of apneas and/or hypopneas rather than differentiating between the two phenomena. Hypopnea is typically defined by a decreased amount of air movement into the lungs and can cause oxygen levels in the blood to drop. It commonly is due to partial obstruction of the upper airway. Hypopnea during sleep is classed as a sleep disorder. With moderate to severe hypopnea, sleep is disturbed such that patients may get a full nights sleep but still not feel rested because they did not get the right kind of sleep. The disruption in breathing causes a drop in blood oxygen level, which may in turn disrupt the stages of sleep. Daytime hypopnea events, however, are mostly limited to those with severely compromised respiratory muscles, as occurs in certain neuromuscular diseases or compromised central respiratory drive, as occurs in conditions such as acquired or congenital central hypoventilation syndrome (ACHS or CCHS). Daytime hypopnea can also cause a drop in blood oxygen level. Symptoms
The most common hypopnea symptom is excessive sleepiness, which results from constant sleep interruption.