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تصاوير بيماري لوك امريكائي(زبان اصلي)

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تصاوير بيماري لوك امريكائي(زبان اصلي)

پستتوسط mellifera » 13 بهمن ماه 1391 19:30


Normal Brood Development

In order to diagnose AFB, it is important to understand the process of normal worker bee development. Identifying brood symptoms involves comparing the appearance of brood that looks abnormal with the appearance of healthy brood. Three days after the queen lays an egg it hatches into a pearly white larva. At this stage, the larva appears as a small c-shape in the bottom of the cell.



The developmental stages of healthy worker brood

Over a 4 day period, the larva remains in this c-shape, greatly increasing in size until it appears to completely fill up the cell. On the 8th day (after the egg was laid), the larva stretches out along the lower wall of the cell in preparation for changing into the adult form (called the “prepupal stage”). On the 9th day, the cell is capped over with wax by house bees.On the 12th day, the larva pupates and the form of the adult bee takes shape. The pupa is initially white in appearance, but gradually changes into its adult colouration. On the 21st day, the new adult worker bee chews a hole in the capping and emerges.



Development of Brood Infected with American Foulbrood

The developmental stages of worker brood infected with AFB are outlined (see below). Larvae are most susceptible to AFB infection when they are less than 24 hours old. Millions of spores are required to infect a larva more than 2 days old, but larvae up to 24 hours old can become infected with ten spores or fewer.

The developmental stages of worker brood infected with AFB

Although the AFB vegetative rods multiply in the gut of the larva, they do not penetrate the gut wall and multiply in its tissues until it stretches out before pupation (prepupal stage). Visual disease symptoms do not become apparent until death occurs, either just before or just after the larva pupates. Infected larvae do not usually exhibit disease symptoms until after the cells have been capped. Where uncapped diseased larvae and pupae are found it is usually because the cappings have been removed by house bees.

VISUAL SYMPTOMS
Colour of Cell Cappings

The first observable symptom of AFB is usually a change in the appearance of cell cappings. Healthy cappings are raised in shape, and range in colour from light to dark brown. Cappings covering infected cells will initially be the same colour as the uninfected cells surrounding them. However, infected cells will eventually become darker in colour until they appear black. Infected cells also develop a moist, almost greasy appearance and become sunken.



Healthy cell capping



Dark sunken cell capping

Holes in Cappings

Even though initially there may be no visible change in the colour of the capping of an infected cell, worker bees can still identify a problem within, and will chew holes in the capping before removing the contents of the cell. The holes can usually be distinguished from holes in the unfinished capping of healthy cells. The holes in infected cell cappings have a more irregular appearance.

Holes will also be created in healthy cells when the young adult worker bees chew apart the cappings to release themselves from cells. These holes will also appear irregular in appearance, but can be easily distinguished from infected cells since a live adult bee will be found underneath the capping.



A cell capping with a hole chewed in it



A cell capping in the process of being sealed



A hole in a capping caused by an emerging bee

Type of Brood

Symptoms of AFB are normally only found in worker larvae and pupae. However, on rare occasions symptoms will be found in drone brood (generally only in heavy infections). Symptoms of the disease are also occasionally found in queen cells.

“Spotty” Brood Pattern

Because larvae infected with AFB fail to emerge, infected cells are often surrounded by empty cells or by younger, healthy larvae. As a result, the brood in a colony with a heavy AFB infection often takes on a spotty pattern. Worker brood in a healthy hive generally has a more solid pattern, caused by the queen laying eggs of similar age in a number of adjacent cells. The eggs develop into larvae and are capped by the house bees at approximately the same time. “Spotty” brood patterns can also be caused by other factors in the colony not related to AFB however, such as laying workers, a failing or inbred queen, or a range of other honey bee diseases.



Spotty brood pattern



Healthy brood pattern

Colour of Brood

Healthy larvae and freshly capped pupae are pearly white in colour. Infected larvae and pupae change from pearly white to a brown colour resembling coffee with milk. The distinctive coffee-brown colour is often considered a definitive symptom of AFB, although brownish-coloured larvae can sometimes be found that have died from causes other than AFB. There is also a significant variation in the colour of AFB infected larvae and pupae, ranging from very pale brown to almost black. The variation depends on the progression of the disease and the degree of drying of the diseased material. After about a month, the infected larvae or pupae will dry out completely and turn totally black. Dried out, infected larvae and pupae are commonly referred to as “scale”.



Healthy prepupa



Coffee coloured AFB



Pupal scale with tongue

Shape of Brood

Healthy larvae and pupae are characteristically plump in shape. In healthy larvae at the prepupal stage, the circular lines of segmentation are clearly visible. In healthy pupae, the shape of all of the external body parts can be seen. When an AFB infection occurs, the first symptom is often a slight change in the colour of the prepupae or pupae. As the infection develops and the brood tissues are consumed, the remains slump down onto the lower wall of the cell. In diseased larvae in the prepupal stage, the lines of segmentation can no longer be determined easily. In diseased pupae, the body parts lose most of their characteristic shape, although the tongue remains upright and prominent.



Healthy pupa



Early stage AFB infected pupa

Position in Cell

Larvae infected with AFB are only ever found stretched out along the lower wall of the cell (prepupal stage). Infected larvae are never found in the c-shape of younger larvae, since the disease-causing bacteria do not penetrate the gut wall until just before the larvae pupate. Prepupae infected with AFB are always found in the characteristic prepupal position, stretched out along the lower wall of the cell, with the head closest to the cell entrance.

Diseased prepupae and pupae are always stretched along the lower wall of its cell




A very early stage AFB infected prepupa slumped on the lower cell wall



An early stage AFB infected prepupa slumped on the lower cell wall



An AFB prepupa slumped on the lower wall of a cell
Pupal Tongue

When larvae and pupae killed by AFB dry out and turn to scale, their flat shape can make them difficult to identify. Remains of larvae can be especially hard to see, since the scale lies completely flat along the lower wall of the cell. Remains of pupae are generally easier to identify, since a thin thread (which is the dried remains of the pupal tongue) can sometimes be seen pointing directly across the face of the cell, from the bottom angle to the top angle of the hexagon. Seeing a tongue, either in a moist, coffee-brown coloured sunken pupae, or in pupal scale, is a definitive diagnosis of AFB, since no other disease is likely to produce such a symptom.



Infected pupa with tongue stretched across the cell

The presence of a pupal tongue stretching across the cell can be used to reliably diagnose AFB.

Smell

Larvae and pupae infected with AFB can exhibit a characteristic foul smell similar to dead fish (hence the name “foulbrood”). The intensity of the smell varies considerably, depending on the number of infected larvae and pupae present and factors such as temperature. Smell should therefore not be relied upon to determine the presence or absence of AFB, no matter whether the disease is in live colonies, dead colonies or stored combs.

The foul smell that can accompany AFB should not be relied upon to determine the presence or absence of AFB.

“Ropiness” of Brood

Larvae and pupae infected with AFB display a characteristic “ropiness” when a small stick is used to slightly stir the diseased tissue in the cell and then the stick is slowly removed The ropiness is thought to be caused by the presence of long chains of the vegetative stage of AFB bacteria intertwining and producing an elastic, binding effect. The ropiness test is a common technique used to diagnose American foulbrood.



Ropiness test

A positive ropiness test will almost always correctly diagnose AFB.

Fluorescence of Scale

AFB scales have been shown to fluoresce when examined under ultraviolet light with a wavelength of 360 nm. As pollen and some moulds also fluoresce, ultraviolet light should not be relied upon to positively identify AFB infections.

Sourced from National Pest Management Strategy, New Zealand























كاربران عزيز : لطفا از درج آگهي و شماره تماس تبليغاتي در تالار اجتناب نموده و در صورت مشاهده حذف خواهد گرديد.(از بخش آگهي و نيازمندي اقدام به ارسال آگهي نماييد)
كاربران عزيز : قبل از ارسال مبحث جديد در تالار جستجو نماييد و از جستجوگر گوگل سايت در صفحه اصلي استفاده نماييد.
كاربران عزيز :در صورت درج تصوير بهتره از بخش اضافه كردن فايل ضميمه استفاده نماييد چون احتمالا ادرس تصاوير بعد از مدتي از سايت مقصد حذف بشه.
كاربران عزيز :لطفا از درج لينك در امضاء خود اجتناب نموده و از بخش لينك زير اواتار كاربري اقدام به درج لينك نماييد.
كاربران عزيز : لطفا از ارسال مباحث مربوط به زنبورعسل از طريق پيغام خصوصي اجتناب نموده و از طريق تالار سوال خود را مطرح نماييد.
كاربران عزيز : در صورت فراموشي رمز عبور و عدم ورود به سايت به مديريت اطلاع دهيد و نام كاربري و پسورد خود را sms نماييد تا مشكل ورود رفع گردد و از ايجاد نام كاربري جديد خوداري نماييد.

(((فروشگاه سایت زنبورعسل))))

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تصاوير بيماري لوك اروپائي(زبان اصلي)

پستتوسط mellifera » 13 بهمن ماه 1391 19:33

European Foulbrood: A Bacterial Disease Affecting Honey Bee Brood
Last Updated: April 27, 2010

    
Get up-close to an elusive honey bee disease.
<a
Causative agent
European foulbrood is caused by the bacterium Melissococcus plutonius. G. F. White is credited with first identifying the correct bacterium that causes European foulbrood in 1908, naming it Bacillus Y which he later renamed Bacillus pluton (Baily 1983). The bacterium was subsequently renamed by several scientists after it became clearly linked to the disease. Baily (1956) isolated the bacterium and, based on morphology, called it Streptococcus pluton. Baily and Collins (1981), later re-classified the bacterium as Melissococcus pluton based on additional culture and chemical knowledge. This was then tweaked due to nomenclature rules to Melissococcus plutonius meaning "pertaining to Pluto or the underworld" instead of M. pluton which means "Pluton, Greek god of the underworld'" (Truper and de Clari 1998).

Fig.2: Larvae infected with M, plutonius can appear deflated with their tracheal system more defined.


As if the changing nomenclature is not enough to confuse, several other bacteria that are only found in association with M. plutonius were at times credited with causing EFB. This is at least partially due to the fact that these bacteria can overgrow M. plutonius and sometimes seem to improve its growth in lab conditions (Baily 1983). These secondary, infective bacteria present with M. plutonius include; Paenibacillus alvei, Achromobacter (Bacterium) eurydice, and Bacillus laterosporus Laubach (Shimanuki 1997). These bacteria are sometimes considered symbiotic and may cause some of the differences in smell and appearance in infected larvae (Baily 1981). There is suspicion that some of these bacteria may have some causal relationship to symptom onset, but this has never been clearly established (Shimanuki 1997).
<a
Life cycle of European foulbrood
Larvae become infected with European foulbrood when they consume brood food that contains the bacteria M. plutonius (Shimanuki 1997). There is also some evidence that transmission may occur from bites of the parasitic mite, Varroa destructor (Kanbar and Engels 2003). Inside infected larva, the bacterial populations concentrate in the food mass in the midgut and the gut peritrophic membrane interface (McKee et al. 2004) where the bacteria then reproduces (Bailey 1983). Depending on the level of infection, and possibly the amount of available food, the infected larva will either survive or die.
The degree of larval mortality, measured in one experiment, was directly related to the duration or amount of bacteria that was fed to the larva. Larvae were found to be more likely to die as increasing amounts of bacteria were fed (McKee et al. 2004). The larvae that survive go on to defecate and pupate, which leaves bacteria on the combs that can be infective for years, even though this bacteria does not produce spores (Baily 1981, 1983). Surviving larvae will become adults with generally lower weight and delayed pupation when compared to their uninfected counterparts, supporting the idea that infection creates higher energy demands (Baily 1960, Mckee et al. 2004). It is noted that an increased food supply from adequate numbers of nurse bees can reduce larval death and observed symptoms. With adequate amounts of food, larvae are more likely to survive (Baily 1983). This may explain why expression of the disease can change sporadically year to year, and season to season, depending on the balance of nurse bee to larvae ratio and thus, the amount of brood food made available to the larvae.

Fig.6: Pictured are off-colored to dull white larvae from a hive infected with European foulbrood. Note the somewhat pronounced tracheal tubes in the melted larvae to the right.


<a
Symptoms of European foulbrood
It is important to not confuse European foulbrood with American foulbrood. These are two very different diseases that require different management and treatment routines. Both are however bacterial brood diseases. Use the table below as an overview to tell the difference between European foulbrood and American foulbrood.
    
European foulbroodAmerican foulbrood


  • Can be slightly ropey with threads less than 1.5cm, but usually not ropey.
  • Odor: sour or none
  • Scale: brown to black, rubbery
  • Stage of Brood: before capped
  • Appearance: twisted, dull to yellow to dark brown, tracheal tubes often visible
  • Coffee color, ropey with a fine thread about 2.5cm
  • Odor: sulfurous, “chicken house”
  • Scale: brown to black, brittle
  • Stage of Brood: after capped
  • Appearance: chocolate brown to black, perforated cappings

Fig.3: Table from Shimanuki and Knox (2000) and Delaplane (1998), Ropey length from Shimanuki (1997), American foulbrood photo by Williams, USDA.





Fig.4: Pictured is a spotty brood pattern with larvae discolored. Taken from a hive with European foulbrood.


A "spotty brood pattern" (Fig. 4) in a honey bee colony can often be the first sign of a wide variety of problems, including EFB. A spotty brood pattern can occur when some larvae die in their cells from a disease, while others survive and become capped resulting in a spotty or shotgun appearance of the capped stage of brood. Many other conditions and situations can cause a spotty brood pattern. For example, an inbred queen can produce a spotty brood pattern when the alleles at the sex locus become homozygous. This produces fertilized, diploid males which are then consumed by worker bees. Although not unique to hives affected with EFB, a spotty brood pattern is a common symptom of EFB.
In hives infected with EFB, dying and dead larvae can become yellow and then brown. A sour, fishy odor may be present or not. Tracheal tubes can become more apparent as the larvae flattens or 'deflates'(Fig.2). The larvae can also twist as they die and can die curled upwards (fig.1). Other times they melt in their cells and will generally be mushy. The remains can be slightly ropey with threads less then 1.5cm long (Shimanuki 1997). To test if the remains are ropey, a toothpick, match, or small stick can be probed into the cell and removed (fig.5). Once dried, a rubbery scale remains.

Fig.5: Probing a larva melted by European foulbrood. Note that the melted larva is usually not ropey.


<a
Confirming diagnosis
Diagnosis of infection with European foulbrood should begin with visual inspections of the above symptoms. Beekeeper's inexperienced with EFB would likely benefit from confirmation of diagnosis before taking action, in case the infection is another bacteria, virus, chilled brood, or some other situation. Confirmation could occur through their state sponsored apiary inspection program, if available, or by the use of an inexpensive and easy to use diagnostic test kit, or sending a sample to the USDA Beltsville Bee Research Laboratory for testing.
Diagnostic field validation kits for EFB are based on monoclonal antibodies of M. plutonius (Tomkies et al. 2009). Samples sent to the USDA Beltsville Bee Research Laboratory for diagnosis will be examined microscopically for the presence of M. plutonius or one of the associated bacteria, which have often eliminated M. plutonius(Smith 2009). Other methods to confirm M. plutonius include: Enzyme-linked immunosorbent assays (ELISA), (Pinnock and Featherstone 1983), a hemi-nested PCR assay (Djordjevic et al. 1998), and quantitative real-time PCR (Roetschi et al. 2008).
For additional information on diagnosing European Foulbrood, see the following two pages.
  
see summary) indicate that yearly recurrence of the disease in infected apiaries is particularly problematic in the UK.
In Switzerland, incidences have increased in recent years (Forsgren et al. 2005). In that country, PCR techniques were used to detect European foulbrood in colonies with and without symptoms, (Belloy et al. 2007 see summary). It was found that in colonies without symptoms in apiaries where other colonies were symptomatic, 90% of the adult bees carried the bacteria. In apiaries without symptoms, but near symptomatic apiaries, 30% of the colonies carried the bacteria, and in apiaries far from symptomatic apiaries, the bacteria could not be detected. This means that it is possible that the bacteria may not be present in regionally isolated areas.
<a
Cultural control

Fig 7: A larva with its cell torn down for visibility, in a bee hive infected with European foulbrood


There are limited options for possible cultural control of this disease. However, as noted above, treatment may not always be necessary in all cases if conditions change that result in disappearance of the disease. Control is sometimes necessary though. Re-queening the colony may have some benefit, due to a break in the brood cycle, and supplying a queen that is more prolific (Shimanuki 1997). There is some evidence of genetic resistance towards the disease (McKee et al. 2004, Shimanuki 1997), but there are no known lines/breeds that are resistant to EFB, including lines bred for hygienic behavior (Spivak per comm). Hygienic lines are however clearly resistant to American foulbrood.
Due to the infectious activity of the bacteria on contaminated combs, moving combs and equipment should be expected to cause cross contamination. In some countries, destruction or sanitation of infected combs and equipment is required. As of 2008 in Switzerland, European foulbrood is a notifiable disease which requires sanitation of apiaries, without the use of antibiotics. This includes the process of burning every infected and weak colony. In a Swiss study, Roetschi et al. (2008 see summary) showed that this process was not very effective as 5 out of 8 sanitized apiaries were reinfected one year later. However, destroying contaminated equipment has proven effective in another study (see "Chemical control").
see summary).
A promising method for controlling European foulbrood has been developed in the U.K., which involves the combination of removing contaminated equipment with the "shook swarm" method along with the use of antibiotics (Waite et al. 2003a see summary). As mentioned above, recurrence of the disease can be a major problem. This method seems to help control recurrence the following year, in addition to disease control the year implemented. See the research summary, Shook Swarm and OTC Antibiotics for European Foulbrood Control for more information. A trial of this method in the U.S. was not found.











كاربران عزيز : لطفا از درج آگهي و شماره تماس تبليغاتي در تالار اجتناب نموده و در صورت مشاهده حذف خواهد گرديد.(از بخش آگهي و نيازمندي اقدام به ارسال آگهي نماييد)
كاربران عزيز : قبل از ارسال مبحث جديد در تالار جستجو نماييد و از جستجوگر گوگل سايت در صفحه اصلي استفاده نماييد.
كاربران عزيز :در صورت درج تصوير بهتره از بخش اضافه كردن فايل ضميمه استفاده نماييد چون احتمالا ادرس تصاوير بعد از مدتي از سايت مقصد حذف بشه.
كاربران عزيز :لطفا از درج لينك در امضاء خود اجتناب نموده و از بخش لينك زير اواتار كاربري اقدام به درج لينك نماييد.
كاربران عزيز : لطفا از ارسال مباحث مربوط به زنبورعسل از طريق پيغام خصوصي اجتناب نموده و از طريق تالار سوال خود را مطرح نماييد.
كاربران عزيز : در صورت فراموشي رمز عبور و عدم ورود به سايت به مديريت اطلاع دهيد و نام كاربري و پسورد خود را sms نماييد تا مشكل ورود رفع گردد و از ايجاد نام كاربري جديد خوداري نماييد.

(((فروشگاه سایت زنبورعسل))))

t.me/mellifera  کانال تلگرام فروشگاه



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Re: تصاوير بيماري لوك امريكائي(زبان اصلي)

پستتوسط yashilchalish » 15 بهمن ماه 1391 18:31

مدیر محترم گروه از زحمات جنابعالی در خصوص به نمایش گذاشتن عکسهای بیماری های لوک متشکریم کاش میشد زحمت ترجمه فارسی مطالب را هم میکشیدید تا دوستان هم بتوانند عمق مطالب را درک نمایند
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Re: تصاوير بيماري لوك امريكائي(زبان اصلي)

پستتوسط mellifera » 15 بهمن ماه 1391 20:02

با سلام در این ادرس میتونین ترجمه کنین.اما باید یکم انگلیسیمون خوب باشه :

http://translate.google.com/

دو تا هم راجب بیماری لوک قرار میدم جهت اشنایی هر چه بهتر با یان دو نوع بیماری:

http://www.mellifera.ir/194//%D8%A8%DB% ... %B3%D9%84/

http://www.mellifera.ir/195//%D8%A8%DB% ... %B3%D9%84/

http://www.google.com/search?q=%D9%84%D ... llifera.ir
كاربران عزيز : لطفا از درج آگهي و شماره تماس تبليغاتي در تالار اجتناب نموده و در صورت مشاهده حذف خواهد گرديد.(از بخش آگهي و نيازمندي اقدام به ارسال آگهي نماييد)
كاربران عزيز : قبل از ارسال مبحث جديد در تالار جستجو نماييد و از جستجوگر گوگل سايت در صفحه اصلي استفاده نماييد.
كاربران عزيز :در صورت درج تصوير بهتره از بخش اضافه كردن فايل ضميمه استفاده نماييد چون احتمالا ادرس تصاوير بعد از مدتي از سايت مقصد حذف بشه.
كاربران عزيز :لطفا از درج لينك در امضاء خود اجتناب نموده و از بخش لينك زير اواتار كاربري اقدام به درج لينك نماييد.
كاربران عزيز : لطفا از ارسال مباحث مربوط به زنبورعسل از طريق پيغام خصوصي اجتناب نموده و از طريق تالار سوال خود را مطرح نماييد.
كاربران عزيز : در صورت فراموشي رمز عبور و عدم ورود به سايت به مديريت اطلاع دهيد و نام كاربري و پسورد خود را sms نماييد تا مشكل ورود رفع گردد و از ايجاد نام كاربري جديد خوداري نماييد.

(((فروشگاه سایت زنبورعسل))))

t.me/mellifera  کانال تلگرام فروشگاه


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کاربران حاضر در اين انجمن: بدون كاربران آنلاين و 1 مهمان


سلام مهمان گرامي؛

مهمان گرامي، براي مشاهده تالار با امکانات کامل ميبايست از طريق ايــن ليـــنک ثبت نام کنيد