Earth Gauge » Diseases

Climate Fact: Musk Ox Parasites and Warming

kraus — Mon, 25 Jan 2010 14:31:48 +0000

In the Canadian Arctic, Musk Oxen endure the long winters and short summers that characterize one of Earth’s most extreme environments. The animals have spent millennia adapting to the brutal cold, but now increases in temperature are presenting new problems. A parasitic species of nematode dwells in the musk oxen lungs and too many nematodes can inhibit respiration in the oxen making them more vulnerable to predators. The nematodes have a larval stage in slugs that live on the tundra and require a certain amount of heat to reproduce and move from larvae to adult. Traditionally, the cold has made it difficult for an adult nematode to reproduce each year and instead they would only reproduce once every two years. From the late 1970’s to 1990, temperatures were generally not warm enough to allow the nematodes to reproduce every year. Around the late 1980’s however, a threshold was reached and from 1990 to 2003 the nematodes reproduced most years and their populations expanded both in number and range. A 50 percent decline in the study area’s musk oxen population was observed from 1988 to 1994.

Seasons: Winter, Spring, Summer, Fall

Source: Kutz, SJ et al. “Global warming is changing the dynamics of Arctic host-parasite systems.” Proceedings of the Royal Society B 272 (2005): 2571-2576.

Climate Fact: Lyme Disease and Spring Rains

administrator — Mon, 29 Jun 2009 21:42:44 +0000

Lyme disease, the most common vector-borne disease in the United States, is mainly confined to the habitat of the deer tick (the disease’s most common transmission source), which is concentrated in the Northeast. In the Northeast since the 1970’s, average spring rainfall has been increasing at a rate of about 0.5 inches per decade, and the number of Lyme disease occurrences in a particular year corresponds to the rainfall levels from two years earlier, particularly the spring rainfall levels. After an adult deer tick feeds on a host, it loses its ability to take up water and may die prematurely if its habitat remains unusually dry. Because a deer tick takes two years to develop from an egg into an adult, a lack of deer tick eggs being laid in a dry year would result in fewer adult deer ticks hatching two years later.

Season: Spring

Sources: McCabe, G.J., and J.E. Bunnell. “Precipitation and the occurrence of Lyme disease in the Northeastern United States.” Vector Borne Zoonotic 4 (2004): 143-8 and Steere, A.C., et al., “The emergence of Lyme disease.” Journal of Clinical Investigation 113 (2004): 1093-1101 and Subak, S. “Effects of climate on variability in Lyme disease incidence in Northeastern United States.” American Journal of Epidemiology 157 (2003): 531-538 and Orloski, K.A., et al. “Surveillance for Lyme disease – United States, 1992-1998.” Surveillance Summaries (MMWR) 49 (2000): 1-11 and U.S. National Oceanic and Atmospheric Administration (NOAA): Climate Prediction Center. 5 January 2005. 26 June 2008 http://www.cpc.ncep.noaa.gov/charts.shtml

Climate Fact: Stagnant Storm Drains

administrator — Fri, 06 Mar 2009 16:38:34 +0000

Over the last 40 years in the eastern U.S., there has been an increase in the frequency during warm months of 30-day periods when there is no rain. These dry spells now occur about twice as often as they did in the 1960’s. Rainfall events push water through municipal sewer and storm water systems. During dry spells, standing water sits in these systems and provides the ideal breeding ground for southern house mosquitoes, which carry West Nile Virus. Less rain, however, generally means fewer small plots of standing water (such as in used tires), where the Asian tiger mosquito, which probably only occasionally carries West Nile Virus, breeds.

Seasons: Spring, Summer, Fall

Sources: Kaiser, Jocelyn. “Drought Portends Mosquito Misery.” Science 301 (2003): 04 and Omahen, Sharon. “Drought drives mosquito numbers high.” Online posting, 3 October 2007. Georgia Faces: The University of Georgia College of Agricultural and Environmental Service. 17 June 2008 and Groisman, PY and Knight RW. “Prolonged Dry Episodes over the Conterminous United States: New Tendencies Emerging during the Last 40 Years.” Journal of Climate 21 (2008): 1850-1862

Climate Fact: Cotton Yields and Climate

administrator — Thu, 05 Mar 2009 23:41:51 +0000

A common cotton disease in the southeast, hardlock, is caused by fungus that is sensitive to changes in temperature and humidity. The disease does better during years when humidity and rainfall levels are above average, especially during the months of July to September, when cotton plants flower and bolls (pods containing 32 seeds from which the cotton fibers grow) mature. In Florida, during the wet and humid year of 2002, hardlock caused crop yields to decrease from 650 pounds per acre to 400, or the equivalent of 20 million dollars in lost yields. Drier and less humid years, on the other hand, discourage fungal growth and favor high yields. Over 50 percent of the variability in yields in the southeastern U.S. can be explained by climate. Years with the highest cotton yields correspond to years with lower than normal sea surface temperatures (SSTs) in the Gulf of Mexico and Atlantic Ocean, where the winds that blow into the southeast during the summer originate. Lower SSTs mean less humidity, and cause relatively dense air to become concentrated in upper level air masses, which discourages convective cloud formation and rainfall.

Seasons: Summer, Fall

Sources: Baigorria, GA et al. “Assessing Predictability of Cotton Yields in the Southeastern United States Based on Regional Atmospheric Circulation and Surface Temperatures.” Journal of Applied Meteorology and Climatology 47 (2008): 76-90 and The University of Florida Education and Research Center. “Cotton/Hardlock.” Accessed Online 1 October 2008 and Cotton’s Journey. “The Story of Cotton.” Accessed Online 1 October 2008

Climate Fact: Parasite Populations

administrator — Wed, 05 Mar 2008 22:03:18 +0000

From the time of its discovery in the 1940’s until about 1990, a single-celled marine parasite (Perkinsus marinus), which can cause massive die-offs of the commercially important Eastern Oyster (Crassostrea virginica), was rarely spotted north of the Chesapeake Bay. Since 1992, however, outbreaks have been occurring as far as 310 miles north of the bay. The winter water temperature off of the East Coast is an important predictor of the parasite’s success. If winter water temperature falls below 37.4 degrees Fahrenheit, the parasite does not reproduce as readily and its numbers become limited. Since the 1960’s, this temperature has been increasing, and the parasite’s range has expanded to the north.

Season: Winter

Sources: Cook, T et al. “The Relationship Between Increasing Sea-surface Temperature and the Northward Spread of Perkinsus marinus (Dermo) Disease Epizootics in Oysters.” Estuarine Coastal and Shelf Science 46 (1998): 587-597 and Blander, K.M. “Global fish production and climate change.” Proceedings of the National Academy of Sciences 104 (2007): 19709-19714.

Climate Fact: Chikungunya Charge

administrator — Tue, 15 Jan 2008 18:06:03 +0000

Chikungunya fever, which has traditionally been confined to Africa and Southern India, is now present in northern Italy. A relative of dengue fever, Chikungunya, which comes from a Makonde (an ethnic group in Southeast Africa) word that means “to become contorted,” causes fever, rashes, and severe bone pain. Europe’s recent warming trend, especially the trend toward warmer winters, has enabled the Asian Tiger Mosquito to survive in the southern part of the continent. The presence of this mosquito, and a recent mutation of the Chikungunya virus, led to last year’s outbreak, which affected 300 residents in the northern Italian towns of Castiglione di Cervia and Castiglione di Ravenna.

Seasons: Winter, Spring, Summer, Fall

Source:Chong, Jai Rui. “A tropical virus moves north.” The Los Angeles Times: 29 December 2007. Accessed Online 4 January 2007

Climate Fact: Amphibian Alarm

administrator — Mon, 30 Jul 2007 21:10:13 +0000

Sixty-seven (67) percent of the 110 known species of Harlequin Frog are now extinct and 80 percent of the species that have disappeared were last spotted in years following abnormally warm events. It is known that the Chytrid Fungus, which kills amphibians, thrives between the temperatures of 17 and 25 degrees Celsius, and grows best at 23 degrees. A large number of Harlequin Frog species live in Costa Rica’s high altitude Monteverde Cloud Forest, where a recent warming trend has resulted in changes in how the Region’s clouds form. These changes mean that the days in the forest are not hot enough and the nights are not cold enough to kill the fungus. This trend is linked to the decline of Harlequin Frogs.

Seasons: Spring, Summer

(Source: Pounds, J.A. et al. Widespread amphibian extinctions from epidemic disease driven by global warming. Nature: 2006 Jan 12; 439 (7073): 161-7.)

Climate Fact: Coral Crisis

administrator — Fri, 27 Jul 2007 21:36:27 +0000

Just seaward of the Florida keys lies a 130 mile long coral reef that extends from Miami to the Dry Tortugas. This reef provides habitat for over 5,500 marine species and buffers Florida and the Keys from storm surges. A combination of rising ocean temperatures, increases in ocean acidity, and runoff from farms and developments, however, is contributing to widespread declines in the world’s coral populations. In just the last fifty years, 30 percent of the world’s coral reefs have died and another 30 percent have been severely damaged. Some researchers estimate that within 25 years, 60 percent of the coral that is alive today will perish.

Seasons: Winter, Spring, Summer, Fall

(Source: Probasco, Mat. “Researchers Warn About Coral Reef Deaths.” The Associated Press 24 October 2006, and United States. Environmental Protection Agency. Climate Change, Wildlife, and Wildlands: A Toolkit for Teachers and Interpreters. Washington: GPO, 2000.)

Climate Fact: Seafood Safety

administrator — Fri, 27 Jul 2007 19:57:23 +0000

In the United States, the leading cause of seafood related stomach illness is a bacterium known as Vibrio parahaemolyticus, which can only survive in waters that are warmer than 59 degrees Fahrenheit. Sea surface temperatures are now the highest that they have been since at least the 1870’s, a phenomenon that has enabled the bacteria to expand its range. Between 1997 and 2004, at one oyster farm in Alaska, the water temperature rose by an average of 0.4 degrees Fahrenheit per year. This enabled the bacteria to become established 620 miles north of any previously known location of the disease, and resulted in food poisoning aboard a cruise ship.

Seasons: Winter, Spring, Summer, Fall

(Sources: McLaughlin, JB et al. “Outbreak of Vibrio parahaemolyticus Gastroenteritis Associated with Alaskan Oysters.” New England Journal of Medicine 353:1463-1470 (2006) and Centers for Disease Control and Prevention: Division of Bacterial and Mycotic Diseases. Vibrio parahaemolyticus. Accessed Online 27 April 2007 )

Climate Fact: Prolific Poision Ivy

administrator — Fri, 27 Jul 2007 17:33:34 +0000

Atmospheric carbon dioxide (CO2) levels have doubled since pre-industrial times. When CO2 levels are high, poison ivy plants grow faster and produce more urushiol – the chemical notorious for causing rashes and other allergic reactions. Every year, more than 350,000 American develop rashes from contact with this plant.

Seasons: Spring, Summer

(Source: Mohan et al. 2006. Proc. Nat. Acad. Sci. 103(24): 9086-9089 http://www.dec.state.ny.us/website/hudson/hvcc1125dww.pdf)

Climate Fact: Livestock Losses

administrator — Fri, 27 Jul 2007 17:03:21 +0000

In addition to causing a swelling of the mouth that can make the tongue appear blue, the livestock virus commonly known as Bluetongue either kills or weakens the animals that it infects. This virus was traditionally considered an African disease and outbreaks in Europe’s southern fringes were only occasional. Since 1998, rising temperatures in Europe have enabled the virus to persist during the Continent’s winters and have encouraged a range expansion of the species of fly that spreads the virus. Outbreaks have now been documented in 12 European countries. In the Netherlands, over 400 farms have been affected and following an outbreak in Germany, some meat markets saw their supplies drop by over one-third.

Season: Winter, Spring, Summer, Fall

(Sources: “Climate Change Pushes Diseases North.” Reuters 9 March 2007. Accessed Online 9 March 2007 and Purse B.V. et al. “Climate Change and the Recent Emergence of Bluetongue in Europe.” Nature Reviews Microbiology, February 2005: Pages 171-181. and World Organization for Animal Health. 2006. Animal Diseases Data: Bluetongue. 9 March 2007 )