Will Polio Be Eradicated?

Polio? What is polio? The only time the majority of people in our world encounter that name is when a physician encourages us to have our children immunized against polio. Polio or poliomyelitis is disease caused by a virus called the polio virus. The virus initially infects either the mouth or the intestines then gets into the bloodstream where it is carried to the spinal cord. Once in the spinal cord the virus reproduces causing damage to the nerves. In severe cases of poliomyelitis the patient becomes paralyzed. The polio virus is highly infectious and can be transmitted person-to-person by a fecal-oral route. There are three different types (P1, P2, and P3) of the polio virus that cause poliomyelitis and a person could theoretically have polio three different times since infection with one type of the virus does not protect against infection with the other types of the virus.

A fecal-oral route of transmission is a transmission route in which infected feces (excrement, bowel movement) from one person ends up in the mouth of an uninfected person. Many people do not wash their hands after using the restroom. After changing a diaper some people forget or are distracted and do not wash their hands.

Even though polio is rare today it was at one time a very common disease. Over 13,000 people each year developed the paralyzing form of polio in the United States during the 1940’s. Most of those with paralytic polio were children. Fortunately, even in that time, less than one in 100 people infected with polio developed paralysis. Most (95%) of the people infected with polio did not have any symptoms. Around 4-8% of people infected with polio had flu-like symptoms. Another 1-2% developed an infection of the membranes surrounding the brain (aseptic meningitis). All of those with flu-like symptoms got over the infection with no long-term problems and nearly every one that got aseptic meningitis were fine in 2 to 10 days. The major problems were associated with those that developed paralytic polio. Many people with paralytic polio got better and their muscles started functioning again. However, there were those every year that did not get better and were either paralyzed for life usually on one side or in some cases died. In the temperate regions of the world, summer was a common time to get polio and many parents kept their children at home in hopes of keeping them safe from polio.

It wasn’t until the mid 1950’s that the vaccine developed by Jonas Salk started to drastically reduce the number of polio victims in the world. Another vaccine developed by Albert Sabin (introduced in 1961) continued the decline in

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Why Our Food Rots II

This is the second edition of “Why our Food Rots.” To get you up to speed, last week’s article described what causes food to rot: MICROBES! I also mentioned the basic methods of food preservation and that changing the temperature of a food can either slow the growth of microbes or kill them. This week’s article will describe how various chemical treatments help in preserving food. The means of preserving food and the chemicals used to preserve the food are as follows:

  • pickling (salt or sugar; vinegar, a weak acid)
  • salting/sugaring
  • fermentation (alcohol)
  • chemical preservation (lots of compounds too long and hard to pronounce for now)

When people think of chemicals they usually think of compounds with long names that are poisonous to life. That is not really true. We are made up of chemicals. Salt and sugar are chemicals that are commonly found in our bodies. There are other chemicals that are not commonly found in us that can be deadly. Lead is a chemical that you don’t want in your body because it is very poisonous.

Unlike lead, chemicals like salt, and sugar are only poisonous in very very very high concentrations. Salt and sugar are also poisonous to microbes when in high concentrations. High concentrations of salt and sugar actually suck the water out of our cells and out of microorganism’s cells. When water levels get too low in a cell the cell will die because the enzymes in the cell can’t do their work. No enzymes working means no energy being produced. No energy leads to cell death.

There are a lot of examples of people using high concentrations of salt or sugar to preserve food. Beef jerky is one example. The meat is dried and salted to preserve it. Pickles are preserved in a salt brine that prevents the growth of microbes in and on the cucumbers. Vinegar is also used in salt brine to increase the acidity of the brine. Microbes are killed by acidic conditions because acid will also destroy the enzymes that make microbes grow. Jams, jellies and sweet pickles are examples of the use of sugar to preserve food.

These preservation techniques don’t kill us because we can lower the concentration of the salt or sugar by diluting them out with other foods we eat and because of the large mass of our bodies compared to the amount of salt or sugar we eat. Unfortunately for the microbes, their cell body mass is very small and as a result concentrations of salt and sugar that have little effect on us are deadly to them.

Physical and Behavioral Attributes of Bonobos: Differences Between Pygmy Chimpanzees and Other Great Apes

Bonobos, or pygmy chimpanzees (Pan paniscus), live in the tropical forest region of Congo. Since their discovery, debate has ensued over whether or not pygmy chimpanzees are a distinct species or a subspecies of the common chimpanzee. Whatever the case, bonobos do possess a substantial number of physical and behavioral characteristics that are distinct from those of common chimpanzees.

Physical Differences

Bonobos and chimpanzees differ in their skull size and shape, with the bonobos’ being smaller. Bonobos have a lower body weight and also differ from chimpanzees in sexual variation / dimorphism (bonobos being less dimorphic), and blood type.

Behavioral Differences

Behaviorally, bonobos differentiate from common chimpanzees in terms of social groups and patterns, food and nutrition, sexual behavior, and social relationships.

Social Groups

In general, the social groups of pygmy chimpanzees are larger than those of common chimpanzees. As well, pygmy groups are more stable and aggregative than those of common chimpanzees; conflicts are resolved more peacefully and the individual survival rate is higher.

Food and Nutrition

In terms of food, common chimpanzees seem to eat a larger quantity and variety of food types. It is unclear, however, whether or not this is a result of the diversity and amount of food available in the two species’ respective habitats. Common chimpanzees, for example, “exploit a wider ecological range to obtain food than pygmy chimpanzees and have developed a higher degree of technical skills. Conversely, the food acquisition skills of pygmy chimpanzees are primarily for obtaining fruits in high trees” (Kano 1992, p. 137).

Sexual Behavior

Bonobos are also unique in their patterns of sexual behavior. Females are nearly always sexually receptive, have friendships with males and other females, and are sexually promiscuous. As a result, there is little sexual competition among males, particularly compared to common chimpanzees.

Social Relationships

Social relationships are more coherent among bonobos. Unity among males is less strong than in common chimpanzees; however, relationships among females and between male and female bonobos are much friendlier than in common chimpanzees (Kano 1992, p. 205). In general then, pygmy chimpanzees have large, stable groups made up of nearly equal numbers of males and females. In contrast to common chimpanzees, bonobos are passive, do not engage in all-male war parties, and have never been witnessed to carry out infanticide (Kano 1992, p. 209; Rumbaugh 1998, p. 3).

Given the stark differences between chimpanzees and bonobos, researchers have been anxious to examine whether or not bonobos would demonstrate a higher (or lower) capacity for human language learning. Because of their temperament and inquisitive nature, it has been proposed that they may be better adept at language training tasks and it has been suggested that bonobos are more intelligent than common chimpanzees.