As elsewhere around the world, when Varroa mites reached England, so did many cases of colony collapse that could not be explained simply by nutrient drain by parasitic mites. In fact, the article, Varroa and Viruses in the U.K. "Bee Biz, No. 7, February 1998), states that under hygienic conditions, mite feeding only temporarily reduces the protein level of the host bee, with no further consequences to the bee. Thus, the mortality associated with mite feeding appears to be pretty much a mite vectored, viral disease problem. However, as in most biological cases, the story is not simply black and white. Some colonies with high virus levels survive while others don't. This suggests that selection and breeding programs could have real value in this battle to protect bees from mites. But, how do you determine which stock or stocks have the complex of desired traits? Usually when you select for one or two traits, you lose or modify others for the worse. Bees don't go along with being manipulated genetically very well at all. FROM Eric Mussen Apiculture Newsletter January/February 1998 * * * The exoskeleton and its cuticular surface are a pretty formidable barrier against microbes. The outer layer of the exoskeleton is covered with a waxy layer that includes unsaturated fatty acids. Besides preventing loss of water (prevents dehydration) and penetration of water (prevents tissues from becoming "water logged"), the waxy layer makes it difficult for microbes to become attached to the surface. It also resists enzymes (chitinases) secreted by microbes that might other-wise be able to eat their way into the insect. While we think of the exoskeleton as protecting the outside of the bee, it extends well into the tracheal system and lines the fore gut and hind gut of the intestinal tract. It has to be sloughed each time the bee molts. Despite that protection, microbes do make their way into honey bees. In the case of fungi, a number have been listed as being pathogenic. Some are regarded as named "bee diseases" like Ascosphaera apis (chalkbrood); Aspergillus flavus, A. fumigatus, and other Aspergillus species (stonebrood); and Nosema apis and N. ceranae (nosema disease). Other fungi have been recorded as agents of "opportunistic" infections. They include Aureobasidium pullulans, Trichoderma lignorum, Mucor hiemalis, Rhizopus species (black bread mold), and various species of Candida, a yeast. It now seems that Dr. Bailey was very prescient in the 1960's. Lots of honey bees have latent viruses in them. If they don't replicate, the viruses don't appear to cause any physical damage to the bee. But, they are showing up in honey bee eggs, larvae, pupae and adults. The research uncovered one more interesting fact. The WHOLE GENOME of the virus could become incorporated into the bee's genome. Then, under the right circumstances, the instructions for virus replication could be activated right from within the bee cell, itself. FROM Eric Mussen Apiculture Newsletter July/August 2007 * * * Sacbrood virus is the most widely distributed of all honey bee viruses. Since its first identification in the United States in 1913, infection of SBV has been found on every continent where A. mellifera honey bees are present. SBV attacks both brood and adult stages of bees, but larvae about 2-day old are most susceptible to SBV infections. SBV affects adult bees without causing obvious signs of disease, but the infected adult bees may have a *decreased life span*. SBV infection has been associated with varroa mite infestation. SBV was detected in large amount of adult bees from varroa mite–infested colonies. Stressful circumstances can favor outbreaks of viral diseases, thus any efforts that strengthen the colony health are expected to reduce the risk of virus infections. Since the varroa mite has been proven to be an effective vector in transmitting and activating viruses, timely and efficient control of the varroa mite population will reduce the incidence of viral diseases. * Viruses can act in new and unexpected ways and new viruses keep emerging, forming additional challenges in the elucidation of viral infections. FROM Honey Bee Viruses Yan Ping (Judy) Chen, and Reinhold Siede **************************************************** * General Information About BEE-L is available at: * * http://www.honeybeeworld.com/bee-l/default.htm * ****************************************************