More than you wanted to know about the cause of “Lash Eggs” and Salpingitis
Written by Annika McKillop DVM, MSpVM, DACPV
Instead of getting your expected egg in the nesting box, one
day you may come into the surprise of finding and egg-shaped ball of caseous
exudate. Caseous means “resembling
cheese or curd” and an exudate is “a fluid with a high content of protein and
cellular debris which has escaped from blood vessels and has been deposited
into tissues or on tissue surfaces as a result of inflammation.” Salpingitis, which means inflammation
of the uterine tube, is the underlying condition producing this exudate. This caseous exudate is essentially pus
coming from the oviduct of a bird.
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| Left: Normal egg laid by a hen. Right: Caseous Exudate or "Lash Egg" laid by a hen |
Causes
There are many causes of salpingitis in Galliformes, and
salpingitis can be found in other female species such as ducks and geese. Salpingitis can be bacterial or viral
in origin, and coinfection of Escheria
coli and Tetratrichomoanas (a
protozoa) can happen in ducks. Salpingitis results following the entry of an
organism from the vagina and ascending the reproductive tract through reverse peristalsis,
infections can descend from the greater abdominal airsac to the oviduct, by the
blood in systemic disease, and spread from other adjacent tissues.
Masses in the oviduct can vary in size. Smaller masses within the oviduct up to
the size of an egg can be passed by birds or can be regurgitated into the
abdominal cavity by reverse paristalsis.
Masses can be so large that they can rarely cause rupture of the oviduct,
but mainly are just so large that they persist in the oviduct until ovulation
ceases, slowing the enlargement of the mass. These enlarged masses cannot be expelled by the birds, and
often press on internal organs and make it difficult for birds to breath as
they cannot get adequate air intake into their airsacs as the mass displaces
them. In younger birds,
salpingitis extends from yolk or air sac infections. The oviduct becomes filled up with the caseous exudate which
persists until maturity, and will be passed just before egg production.
Bacterial Salpingitis
Salpingitis caused by bacteria tends to be more exudative,
causing “lash eggs” that are large and firm. Contents of the masses include exudate, yolk, egg shells,
membranes, oviduct tissue, and oviduct secretions that are malodorous. When caseous masses are cut into, they
can be described as having an onion-layered texture, or a progressive
accumulation of concentric layers of material. Sometimes fully formed eggs can be found in the caseous mass
as a result of egg binding or because the egg became lodged in the oviduct in
an area of localized inflammation.
The main bacteria and most prevalent cause of infection is E. coli, but other bacterial causes
include Staphylococcus aureus, Gallibacterium, Mycoplasma spp., and Salmonella, Klebsiella spp., and Pseudomonas spp..
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| Caseous Exudate laid by a chicken and cut open showing accumulation of concentric layers of material. |
Viral Salpingitis
Viral Salpingitis lesions, according to Avian
Histopathology, contain “edema, hemorrhage and pale, turbid, creamy or
gelatinous exudate.” Viral
causes are most commonly Infectious Bronchitis Virus, but can also include
adenoviruses, Newcastle disease and influenza viruses.
Clinical Signs
Birds showing signs of salpingitis include birds with a
“Penguin Stance” due to abdominal swelling, abdominal firmness upon palpation, labored
breathing (as material increases in the oviduct, it replaces the area for birds
to expand their airsacs and also presses on other abdominal organs), decreased egg
production, eggs with abnormal shape, wrinkles in
the shells, thin watery albumen in the egg, laying of soft-shelled and “lash” eggs,
lethargy, and death.
Predisposing factors include age, malnutrition, vent pecking, excessive
abdominal fat/over nutrition, and excessive and/or prolonged egg laying.
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| Chicken exhibiting a "Penguin Stance" |
Prevalence
Multiple studies, personal experience, and discussion of the
syndrome with other poultry veterinarians have shown that salpingitis is the
number one cause of death in poultry layers in the commercial poultry
industry. To date, there has not
been a study to show what the number one cause of death is in backyard poultry,
but with personal experience, salpingitis is frequently seen in backyard
flocks, especially in older birds.
The most common disease I encounter in backyard poultry practice is Mycoplasma species.
Treatment
Antibiotics, such as tetracyclines, can be used to treat
salpingitis of bacterial origin if the infection is caught early enough. Antibacterial treatment will vary
depending on the bacteria and susceptibility of that organism to antimicrobial
therapies. There is no treatment
for salpingitis of viral origin.
When treating laying hens with antibiotics, there is always
a withdrawal time associated with the drug being used. Contact a veterinarian for the
appropriate withdrawal time set by Food Animal Residue Avoidance Databank
(FARAD). Some drugs, such as
fluoroquinolones, including Baytril (Enrofloxacin), choramphenical,
nitroimidazoles, and glycopeptides (including Vancomycin) are illegal to use in
poultry in the United States, regardless if the animal is a pet. The use of medication in feeds cannot
be used off label, which means it cannot be used differently than what the Food
and Drug Administration (FDA) has approved. According to FARAD, which is a congressionally-mandated
risk-management program in food animals supported by the United States
Department of Agriculture (USDA):
“Under provisions of the American
Medicinal Drug Use Clarification Act (AMDUCA) and 21
CFR part 530, FDA can prohibit use of an entire class of drugs in selected
animal species if FDA determines that: (I) an acceptable analytical method
needs to be established and such a method has not or cannot be established; or
(II) the extra-label use of the drug or drug class presents a public health
risk. FDA can also limit the prohibition on extra-label use to specific
species, indications, dosage forms, routes of administration, or a combination
of these.”
Surgery is an option, but you will need to go to an avian
veterinarian that has surgical experience in birds and willingness to remove
the oviduct in chickens. This is
very costly, and there are always risks to be considered when doing surgery. Removal of the oviduct is essentially
an exploratory surgery, and depending on the severity of the lesions (inclusion
of peritonitis which is visualized upon opening the bird), prognosis is very
poor, and a decision if the bird should be euthanized on the table can be
warranted. When pus/lash eggs or
eggs are removed (without removal of the oviduct), there is a significant
increased risk of reoccurrence.
Hormone therapy has been illegal in the United States in
poultry since the 1950’s, so hormone implants in the United States are not an
option. They may be an option in
other countries depending on their regulations in poultry. When discussing salpingitis with over
poultry veterinarians, one of the best ways to help with salpingitis is to
bring birds out of production. The
best method is to decrease the amount of light and change feed to a molting
type of feed, especially if salpingitis is a flock problem.
Euthanasia is also an option, depending on the severity of
infection in the bird. Decision of
euthanasia is based on examination, symptoms, and quality of life.
Recovery?
Recovery depends on how far the infection has progressed, how
early it is detected, and also if the bacterial infection has spread through
the oviduct and started infecting other parts of the body (peritonitis). Recovery and prognosis is therefore
determined on a case-by-case basis.
If caught early on while the infection is still soft or not as extensive,
you can treat with antibiotics and the bird can recover. Birds that do recover do not have the
same reproductive potential, and are also at higher risk of laying more lash
eggs and oviduct obstruction.
Prevention
Good biosecurity
is the first and foremost prevention of any poultry disease. First start with clean chicks that come
from a flock free of Mycoplasma, Salmonella, Avian Influenza, and Pullorum/Typhoid. Flocks free of thise diseases can be found
on the National Poultry Improvement Plan website in their database of tested
NPIP flocks. Also, getting birds
of good chick quality decreases the chance of yolk sac infections, and good
bird management/hygiene.
What if you come home with a new addition?
- Keep your new birds separated from the birds you already have for a month. This is called a quarantine period. Why? If the new birds have a contagious disease, they will most likely show symptoms within the first month. You can try to prevent spreading the disease to the birds you already have. Some birds carrying diseases may not show symptoms of disease during this time, so the best thing to do when bringing a bird into the flock is to test them during the quarantine period.
- Take care of the birds you already have first, then take care of your new birds second. If you need to go back and take care of your original birds again, take a shower and change your cloths.
- Wash your hands before and after working with each group of birds, not only for their safety, but for yours as well.
- Wash and disinfect equipment. Wash dirt/feces off equipment with soap and water, rinse well, then apply disinfectants such as Virkon, gluteraldehyde, phenols, alkalis, and hypochlorites. Most disinfectants are inactivated by dirt and feces, so be sure to clean with soap and water and rinse well. You can also use a solultion of three parts bleach to two part water, and use it liberally to disinfect rubber boots and equipment.
- Have designated shoes for each group of birds.
If you come in contact or are around other poultry:
- Take a shower when you get home, and change your clothes/shoes before going around your birds.
- Wash your car in a car wash on your way home. When you and your car visit places that have a lot of different birds, its not just you that carries disease.
- Better yet, keep designated clothes and shoes for when you work with your birds! Why? You can carry diseases on your cloths, shoes, and car from birds/products that you visit or come in contact with. Imagine a person that is sick, sneezes on their hand, and touches the doorknob someone is going to use after them. Disease is transmitted via the doorknob. You essentially become the doorknob between the sick bird and your birds, and you have the potential to carry disease home.
Other ways to prevent Salpingitis is good quality feed that
is balanced (don’t overfeed treats or give “people food”, especially processed
foods such as breads, cakes and pastas. Birds can be vaccinated for diseases
present in the area, and all birds that unexpectedly die should have a necropsy
performed to make sure it isn’t a contagious disease that can be spread to the
rest of the flock.
Urban Legends
I have consulted with four other veterinary experts in the
poultry field about the following urban legends. Their credentials include over forty years experience,
diverse background in layers including backyard and industry, academia, and
board certification by the American College of Poultry Veterinarians.
When birds get sick,
they can get such high fevers that eggs will cook inside of them.
This is false.
According to the National Egg Council, United States Library of
Commerce, and Bill Nye the Science Guy who did his own experiment, the minimum temperature to start
cooking an egg is between 130 and 144 degrees Fahrenheit, with a temperature of
158 degrees to become firm. Even
at a lower temperature of 130 degrees, it takes at least 20 minutes. Birds will die when reaching the
temperature of 110 degrees Fahrenheit, and soon after perishing, the body
temperature starts to rapidly decrease.
Lash eggs are caused
by normal sloughing-off of the oviduct.
This is false.
The oviduct is a secratory organ that will regress during times when
birds are not in production. Lash
eggs are caused by bacterial and viral infections of the oviduct.
I want to thank my colleagues for their input on the subject, and also to Kathy Mormino AKA the Chicken Chick for the WONDERFUL pictures and excellence in providing accurate information to poultry enthusiasts.
~ Dr. McKillop is a licensed veterinarian
and practices veterinary medicine in Maryland and Pennsylvania. Dr. McKillop is the Founder and Owner of McKillop Poultry Medicine, LLC. She has a Masters in Specialized
Veterinary Medicine, completed a residency in poultry medicine at North
Carolina State University, and is a boarded Diplomat of the American College of
Poultry Veterinarians. You can follow McKillop Poultry Medicine, LLC on Facebook.
References:
1) Saunders Comprehensive Veterinary Dictionary, 2nd
Edition
2) Avian Histopathology, 3rd Edition. 2008
3) Diseases of Poultry, 12th edition YM Saif
4) Salpingitis
in poultry. I. Prevalence, bacteriology and possible pathogenesis in broilers.
Nord Vet Med. 1980 Sep;32(9):361-8.
5) Salpingitis in Pekin ducks associated with concurrent
infection with Tetratrichomonas sp. and Escherichia coli. Crespo R, Walker RL,
Nordhausen R, Sawyer SJ, Manalac RB. J Vet Diagn Invest. 2001 May;13(3):240-5.
6) Diseases and Disorders of the Domestic Fowl and Turkey
7) Avian Disease Manual, 7th Edition Edited by
Martine Boulianne. 2013
8) Avian Medicine and Surgery in PracticeBob Doneley, 2010
9) Poultry Health Handbook, 4th Edition. L. Dwight Schwartz, DVM. 1994
10) Library of Congress. http://www.loc.gov/rr/scitech/mysteries/friedegg.html
Accessed 3/16/15
11) Food Animal Residue Avoidance Databank. http://www.farad.org
12) A Practical Guide for Managing Risk in Poultry
Production, 2011
13) Live
Science. http://www.livescience.com/37860-hot-enough-to-fry-an-egg-on-the-sidewalk-this-weekend.html
accessed 3/16/2015
