Cold Temperature Exposure

It's easy to get cold quickly if you are outside in wet, windy, or cold weather. Cold temperature exposure can also happen if you spend time in a dwelling or other building that is not well-heated during cold weather.

Injuries from cold exposure:

* "Frost nip" usually affects skin on the face, ears, or fingertips. Frost nip may cause numbness or blue-white skin color for a short time, but normal feeling and color return quickly when you get warm. No permanent tissue damage occurs.
* Frostbite is freezing of the skin and the tissues under the skin because of temperatures below freezing. Frostbitten skin looks pale or blue and feels cold, numb, and stiff or rubbery to the touch.
* Cold injuries, such as trench foot or chilblains, may cause pale and blistered skin like frostbite after the skin has warmed. These injuries occur from spending too much time in cold, but not freezing, temperatures. The skin does not actually freeze.
* An abnormally low body temperature (hypothermia) occurs when the body loses heat faster than it can make heat. Early symptoms of hypothermia include shivering in adults and older children, clumsy movements, apathy (lack of concern), poor judgment, and cold, pale, or blue-gray skin. Hypothermia is an emergency condition—it can quickly lead to unconsciousness and death if the heat loss is not stopped.

Risk factors for cold exposure injury:

There are many factors that increase your risk of injury from exposure to cold temperatures.

* Being a baby
* Being an older adult
* Drinking alcohol
* Being in outdoor conditions, such as high altitudes or windy, wet weather, or being immersed in cold water
* Not being dressed properly, having wet skin, or wearing wet clothing
* Being tired or dehydrated
* Being exposed to cold temperatures in your workplace, such as working in cold-storage units
* Having certain health risks

Many people get cold hands or feet, which often are bothersome but not a serious health problem.

You are more likely to feel cold easily if you:

* Do not have much body fat. Fat under the skin helps keep you warm. People who have low body fat may be more likely to get hypothermia. Babies, older or ill adults, or malnourished people have low body fat.
* Smoke cigarettes or drink caffeine. Nicotine (from tobacco) and caffeine cause narrowing of the blood vessels in the hands and feet. When blood vessels are narrowed, less blood flows to these areas, causing the hands and feet to feel cold.
* Are under a lot of stress or feel tired. Chronic stress or anxiety can cause your nervous system to release adrenaline, which acts to narrow the blood vessels that supply blood to the hands and feet.
* Have a medical condition, such as hypothyroidism or Raynard's phenomenon, that makes you feel or react more strongly to cold temperatures.

Infection - What Happens

There are two types of HIV:

* HIV-1, which causes almost all the cases of AIDS worldwide
* HIV-2, which causes an AIDS-like illness. HIV-2 infection is uncommon in the United States.

How the disease is spread:

HIV is spread when blood, semen, or vaginal fluids from an infected person enter another person's body, usually through:

* Sexual contact. The virus may enter the body through a tear in the lining of the rectum, vagina, urethra, or mouth. Between 75% and 80% of all cases of HIV are transmitted by sexual contact.
* Infected blood. HIV can be spread when a person:
o Shares needles, syringes, cookers, cotton, cocaine spoons, or eyedroppers used for injecting drugs or steroids.
o Is accidentally stuck with a needle or other sharp item that is contaminated with HIV.

It is now extremely rare in the United States for HIV to be transmitted by blood transfusions or organ transplants. Blood and organ donors are screened for risk factors. All donated blood and organs are screened for HIV.

Health care workers are no longer considered to be at high risk of exposure to HIV. Policies are in place in health facilities that require protection from accidental exposure. Workers must properly dispose of sharp objects and wear protective gloves, gowns, and eye and face protection. These measures have been effective in protecting health care workers from HIV.

Spread of HIV to babies:

A woman who is infected with HIV can spread the virus to her baby during pregnancy, delivery, or breast-feeding.

* Most children younger than 13 years who have HIV were infected with the virus by their mothers.
* The risk of a woman spreading HIV to her baby can be greatly reduced if she is on medicine that reduces her viral load (HIV RNA) to undetectable levels during pregnancy, if she receives AZT (ZDV) before the baby is born, and if she does not breast-feed her baby. The baby should also receive treatment after it is born.

Ways HIV cannot be spread:

HIV does not survive well outside the body. Therefore, HIV cannot be spread through casual contact—such as sharing drinking glasses or by casual kissing—with an infected person. HIV is not transmitted through contact with an infected person's saliva, sweat, tears, urine, or feces, or through insect bites.

Contagious and incubation period:

The incubation period—the time between when a person is first infected with HIV and when early symptoms develop—may be a few days to several weeks.

It can take as little as 2 weeks or as long as 6 months from the time you become infected with HIV for the antibodies to be detected in your blood. This is commonly called the "window period," or seroconversion period. During the window period, you are contagious and can spread the virus to others. If you think you have been infected with HIV but you test negative for it, you should be tested again 6 months later.

After you become infected with HIV, your blood, semen, or vaginal fluids are always infectious, even if you receive treatment for the HIV infection.

Stages of HIV:

Most people go through the following stages after being infected with HIV if the infection is not treated:

* Acute retro viral syndrome, which has symptoms similar to mononucleosis. This often develops within a few days of infection, but may occur several weeks after the person is infected.
* HIV without symptoms (asymptomatic). It may take years for HIV symptoms to develop. But even though no symptoms are present, the virus is multiplying (or making copies of itself) in the body during this time. HIV multiplies so quickly that the immune system cannot destroy the virus. After years of fighting HIV, the immune system starts to weaken.
* HIV with symptoms (symptomatic). After your immune system starts to weaken, you are more likely to develop certain infections or illnesses, such as some types of pneumonia or cancer that are more common in people who have a weakened immune system.
* AIDS, which occurs during the last stage of infection with HIV. If HIV goes untreated, AIDS develops in most people within 12 to 13 years after the initial infection. With treatment for HIV, the progression to AIDS may be delayed or prevented.

A small number of people who are infected with HIV are rapid progressors. They develop AIDS within a few years if they do not receive treatment. It is not known why the infection progresses faster in these people.

Nonprogrammable and HIV-resistant:

A few people have HIV that does not progress to more severe symptoms or disease. They are referred to as nonprogrammer.

A small number of people never become infected with HIV despite years of exposure to the virus. For example, they may have repeated, unprotected sex with an infected person. These people are said to be HIV-resistant.

Heat-Related Illnesses

A healthy body temperature is maintained by the nervous system. As the body temperature increases, the body tries to maintain its normal temperature by transferring heat. Sweating and blood flow to the skin (thermo regulation) help us keep our bodies cool. A heat-related illness occurs when our bodies can no longer transfer enough heat to keep us cool.

A high body temperature (hypothermia) can develop rapidly in extremely hot environments, such as when a child is left in a car in the summer heat. Hot temperatures can also build up in small spaces where the ventilation is poor, such as attics or boiler rooms. People working in these environments may quickly develop hypothermia.

High temperature caused by a fever is different from a high body temperature caused by a heat-related illness. A fever is the body's normal reaction to infection and other conditions, both minor and serious. Heat-related illnesses produce a high body temperature because the body cannot transfer heat effectively or because external heat gain is excessive.

Heat-related illnesses include:

* Heat rash (prickly heat), which occurs when the sweat ducts to the skin become blocked or swell, and cause discomfort and itching.
* Heat cramps, which occur in muscles after exercise because sweating causes the body to lose water, salt, and minerals (electrolytes).
* Heat edema (swelling) in the legs and hands, which can occur when you sit or stand for a long time in a hot environment.
* Heat tetanus (hyperventilation and heat stress), which is usually caused by short periods of stress in a hot environment.
* Heat syncope (fainting), which occurs from low blood pressure when heat causes the blood vessels to expand (dilate) and body fluids move into the legs because of gravity.
* Heat exhaustion (heat prostration), which generally develops when a person is working or exercising in hot weather and does not drink enough liquids to replace those lost liquids.
* Heatstroke (sunstroke), which occurs when the body fails to regulate its own temperature and body temperature continues to rise, often to 105°F (40.6°C) or higher. Heatstroke is a medical emergency. Even with immediate treatment, it can be life-threatening or cause serious long-term problems.

Often, environmental and physical conditions can make it difficult to stay cool. Heat-related illness is often caused or made worse by dehydration and fatigue. Exercising during hot weather, working outdoors, and overdressing for the environment increase your risk. Caffeine or alcohol also increase your risk for dehydration.

Many medicines increase your risk of a heat-related illness. Some medicines decrease the amount of blood pumped by the heart (cardiac output) and limit blood flow to the skin, so your body is less able to cool itself by sweating. Other medicines can alter your sense of thirst or increase your body's production of heat. If you take medicines regularly, ask your doctor for advice about hot-weather activity and your risk of getting a heat-related illness.

Other things that may increase your risk of a heat-related illness include:

* Age. Babies do not lose heat quickly and they do not sweat effectively. Older adults do not sweat easily and usually have other health conditions that affect their ability to lose heat.
* Obesity. People who are overweight have decreased blood flow to the skin, hold heat in because of the insulating layer of fat tissue, and have a greater body mass to cool.
* Summer heat waves. People who live in cities are especially vulnerable to illness during a summer heat wave because heat is trapped by tall buildings and air pollutants, especially if there is a high level of humidity.
* Chronic diseases, such as diabetes, heart failure, and cancer. These conditions change the way the body gets rid of heat.
* Travel to wilderness areas or foreign countries with high outdoor temperatures and humidity. When you go to a different climate, your body must get used to the differences (acclimate) to keep your body temperature in a normal range.

Most heat-related illnesses can be prevented by keeping the body cool and by avoiding dehydration in hot environments. Home treatment is usually all that is needed to treat mild heat-related illnesses. Heat exhaustion and heatstroke need immediate medical treatment.

The spectrum of kidney disease in patients with AIDS in the era of antiretroviral therapy

With prolonged survival and aging of the HIV-infected population in the era of antiretroviral therapy, biopsy series have found a broad spectrum of HIV-related and co-morbid kidney disease in these patients. Our study describes the variety of renal pathology found in a prospective cohort of antiretroviral-experienced patients (the Manhattan HIV Brain Bank) who had consented to postmortem organ donation.

Nearly one-third of 89 kidney tissue donors had chronic kidney disease, and evidence of some renal pathology was found in 75. The most common diagnoses were arterionephrosclerosis, HIV-associated nephropathy and glomerulonephritis. Other diagnoses included pyelonephritis, interstitial nephritis, diabetic nephropathy, fungal infection and amyloidosis.

Excluding 2 instances of acute tubular necrosis, slightly over one-third of the cases would have been predicted using current diagnostic criteria for chronic kidney disease. Based on semi-quantitative analysis of stored specimens, pre-mortem microalbuminuria testing could have identified an additional 12 cases.

Future studies are needed to evaluate the cost-effectiveness of more sensitive methods for defining chronic kidney disease, in order to identify HIV-infected patients with early kidney disease who may benefit from antiretroviral therapy and other interventions known to delay disease progression and prevent complications.

Heterosexual risk of HIV-1 infection per sexual act

Thelancet did a systematic review and meta-analysis of observational studies of the risk of HIV-1 transmission per heterosexual contact.

43 publications comprising 25 different study populations were identified. Pooled female-to-male (0·04% per act [95% CI 0·01—0·14]) and male-to-female (0·08% per act [95% CI 0·06—0·11]) transmission estimates in high-income countries indicated a low risk of infection in the absence of antiretrovirals.

Low-income country female-to-male (0·38% per act [95% CI 0·13—1·10]) and male-to-female (0·30% per act [95% CI 0·14—0·63]) estimates in the absence of commercial sex exposure (CSE) were higher. In meta-regression analysis, the infectivity across estimates in the absence of CSE was significantly associated with sex, setting, the interaction between setting and sex, and antenatal HIV prevalence.

The pooled receptive anal intercourse estimate was much higher (1·7% per act [95% CI 0·3—8·9]). Estimates for the early and late phases of HIV infection were 9·2 (95% CI 4·5—18·8) and 7·3 (95% CI 4·5—11·9) times larger, respectively, than for the asymptomatic phase. After adjusting for CSE, presence or history of genital ulcers in either couple member increased per-act infectivity 5·3 (95% CI 1·4—19·5) times versus no sexually transmitted infection. Study estimates among non-circumcised men were at least twice those among circumcised men. Low-income country estimates were more heterogeneous than high-income country estimates, which indicates poorer study quality, greater heterogeneity of risk factors, or under-reporting of high-risk behaviour.

Efforts are needed to better understand these differences and to quantify infectivity in low-income countries.

Use of Saliva as a Lubricant in Anal Sexual Practices Among Homosexual Men

Objectives: Compared with other sexually active adults, men who have sex with men (MSM) are more frequently infected with several pathogens including cytomegalovirus, hepatitis B virus, and Kaposi sarcoma-associated herpesvirus. Because one common element between these organisms is their presence in saliva, we evaluated saliva exposure among MSM in a heretofore relatively unrecognized route-via use of saliva as a lubricant in anal sex.

Methods: MSM in a San Francisco population-based cohort were interviewed regarding use of saliva by the insertive partner as a lubricant in various anal sexual practices.

Results: Among 283 MSM, 87% used saliva as a lubricant in insertive or receptive penile-anal intercourse or fingering/fisting at some point during their lifetime; 31%-47% did so, depending upon the act, in the prior 6 months. Saliva use as a lubricant was more common among younger men and among HIV-infected men when with HIV-infected partners. Even among MSM following safe sex guidelines by avoiding unprotected penile-anal intercourse, 26% had anal exposure to saliva via use as a lubricant.

Conclusions: Among MSM, use of saliva as a lubricant is a common, but not ubiquitous, practice in anal sex. The findings provide the rationale for formal investigation of whether saliva use in this way contributes to transmission of saliva-borne pathogens in MSM.

Short-Term and Long-Term Effects of Highly Active Antiretroviral Therapy on the Incidence of Herpes Zoster in HIV-Infected Children

Levin, Myron J MD*; Anderson, Jeffrey P MPH†‡; Seage, George R III ScD†‡; Williams, Paige L PhD†§; for the PACTG/IMPAACT 219C Team

From the *Department of Pediatrics, University of Colorado at Denver Health Sciences Center, Aurora, CO; †Center for Biostatistics in AIDS Research; ‡Department of Epidemiology; and §Department of Biostatistics, Harvard School of Public Health, Boston, MA.

Received for publication July 1, 2008; accepted November 14, 2008.

Supported by funding from the Statistical and Data Analysis Center at Harvard School of Public Health, under the National Institute of Allergy and Infectious Diseases cooperative agreement #5 U01 AI41110 with the Pediatric AIDS Clinical Trials Group and #1 U01 AI068616 with the International Maternal Pediatric Adolescent AIDS Clinical Trials Group. Overall support for International Maternal Pediatric Adolescent AIDS Clinical Trials was provided by the National Institute of Allergy and Infectious Diseases [U01 AI068632] and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

A portion of this analysis was presented at the 13th Conference on Retroviruses and Opportunistic Infections, February 5-8, 2006, Denver, CO.

All of the authors made substantial contributions to the conception, design, acquisition of data, and analysis and interpretation of data for this article; contributed substantially to the drafting and revision of this article; and have given final approval for submission of this article.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Allergy and Infectious Diseases or the National Institutes of Health.

Background: Highly active antiretroviral therapy (HAART) has reduced herpes zoster (HZ) incidence in HIV-infected children, yet it remains common.

Methods: We evaluated perinatally HIV-infected youth with varicella infection enrolled between 1993 and 2006 in a prospective cohort study. Incidence rates (IRs) and 95% confidence intervals of HZ were estimated by calendar year, age group, and HAART use. The effect of initiating HAART was also evaluated by fitting Cox survival models adjusted for potential confounders.

Results: Among 536 perinatally infected children with documented prior varicella (median follow-up = 6.8 years), 116 (22%) developed HZ (IR = 3.2 events/100 person-years, confidence interval: 2.6 to 3.8). IRs increased from 1993 to 1996 and then declined significantly through 2006 (P <>

Conclusions: Although HAART has markedly reduced the IR of HZ, it remains a frequent complication in HIV-infected children. The risk of HZ is similar in the 90 days before and after initiating HAART.