An Introduction to Mycoplasmosis and Zamityl

Written by Kevin B.H. Teh (DVM)

Mycoplasmosis – A looming threat

What is Mycoplasmosis?

Mycoplasma is one of the economically important bacterial pathogens in commercial poultry production. The disease is distributed worldwide and affects both the broiler and laying birds causing substantial economic loss due to respiratory infections, arthritis, drop in egg production, abnormalities in egg quality, high morbidity and decreased weight gain. Despite the poultry industry’s best efforts, mycoplasma-related respiratory diseases remain a significant threat.

Living with an invisible illness

Why Mycoplasmosis is so complex

Mycoplasma are very small, slow-growing bacteria which lack a cell wall. Because of their small genome and the absence of many metabolic pathways, they are fastidious microorganisms having complex nutritional requirements. Mycoplasma colonies have a typical ‘fried egg’ appearance on culture media.

Types of Mycoplasmosis

There are two main types of mycoplasma which affect poultry. Both Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS), can make birds ill, sometimes resulting in death, especially if the birds have other existing complications or compromised immune systems. MG is the most pathogenic poultry mycoplasma, while MS is even more fastidious than MG making diagnosis a more difficult process.

Mycoplasma is everywhere. It all starts with one…


Birds with mycoplasma can spread the disease even before exhibiting symptoms. Transmission can be possible within a flock by contact with the droppings, feathers and respiratory secretions of infected birds. Transmission of mycoplasma between the flocks is likely through dust in the air and wind. Its small size and weight allows it to be carried up to 8 kilometers in the air on dust or dander particles. Once infected, the birds become carriers. They can continue to spread even after sick birds are recovered or removed.

Animal and insect.

Animals and insects, such as dogs, rats, beetles and flies, can still carry mycoplasma into areas near birds and infect the flock.

People and fomite.

People can infect flocks without realizing it. Contaminated feed, water, cages and farm tools used around birds contaminated with mycoplasmacan spread the bacteria to other birds. Infection can be carried on shoes, clothing, skin and hair, even if there has not been direct contact with any birds.  Mycoplasma can be carried in the human nose. Work done on synthetic hair showed survival times of up to 9 days.

Mycoplasma can survive longer in moist litter, water, soil and in egg material. Some strains of mycoplasma transmit very well and persist in the environment. They can remain infective for 2 – 3 days on feathers and various materials such as cotton, rubber and wood.

Brown Layer hens on poultry farm - preventing Mycoplasmosis with Zamityl Soluble | Zamira Australia

What’s the connection?

Hens can spread mycoplasma through their eggs to their chicks. Transmission of mycoplasma from infected breeder birds to chicks is one of the major routes of spreading the infection. Chicks that are infected through egg transmission typically show symptoms of mycoplasma within a few days after hatching.

Infection can stay hidden

Infection may be hidden in some birds for days to weeks. When the birds are stressed, the disease can spread through the flock by respiratory secretions. Once the birds are infected, they remain infected for life and act as carriers for the infection.

The transmission occurs readily through contact from the movement of birds, animals, insects, people or fomites from infected to susceptible flocks.

Symptoms of Mycoplasmosis

This is what you see…

Mycoplasma may take up to weeks for birds to exhibit any symptoms, otherwise healthy-looking birds may already be infected with mycoplasma.

Birds infected with mycoplasma are usually depressed, eat and drink less, lose weight, lay fewer eggs than normal and have unusual eggshell appearance. Morbidity typically is high and mortality low in uncomplicated cases.

They may have signs of gasping, foamy eyes, sneezing, nasal discharge and swollen eyelids. While birds infected with MS may have swollen joints and blisters. They appear to have ruffled feathers and usually have problems with standing and reluctant to walk due to lameness.

…but this is what you don’t see

Mycoplasma can spread easily among birds and it has a wide variety of symptoms, but even in the absence of obvious signs, the economic impact may be substantial. It causes subclinical infections and systemic reactions in birds by affecting multiple organs such as the respiratory tract and joints. Mycoplasma can mutate rapidly, and strains can vary widely in infection severity.

Visible symptoms may take weeks to develop, delaying the diagnosis.

Both MS and MG can act synergistically with other respiratory tract pathogens. In the case of combination with secondary infections, especially in combination with other pathogens such as Newcastle disease virus, Infectious Bronchitis virus and E. coli, mycoplasma becomes systemic, causing acute and chronic infection.

The impact of mycoplasma

Hidden costs of infectious respiratory diseases and skeletal disorder

The biggest impact of mycoplasma infection in layer and breeder birds is a dramatic reduction or ‘rollercoaster’ appearance in egg production and abnormalities in eggshell, accompanied by respiratory disease and increased mortality. It is a major concern for the commercial producers because it greatly affects production performance and is a primary consideration for international trade.

Mycoplasma can be transmitted to commercial broilers by infected eggs. Once MG and MS make their way into a commercial poultry operation, the result can be a severe respiratory challenge with high mortality and lameness. Mycoplasma can affect feed conversion and uniformity in birds, leading to an increase in condemnations in the processing plant.

Most of the poultry farms in many countries are multi-age.  Mycoplasma can remain on multi-age farms mostly through infected birds. Once mycoplasma has infected a poultry farm, the only eradication is to depopulate and repopulate with mycoplasma-free flocks.

What you can do

Be aware and act now – treating Mycoplasmosis

Once birds are infected with mycoplasma, they can be treated, but some are likely to remain carriers after recovery. Keeping flocks mycoplasma-free is the method of prevention. Treating infected birds with antibiotic medication may alleviate symptoms, cut down recovery time, help reduce transmission to susceptible birds and production losses.

Many antibiotics work by inhibiting cell wall growth. Because mycoplasma do not have a cell wall, they are naturally resistant to antibiotics that inhibit cell wall synthesis.

There is a cure for Mycoplasmosis

A path to breathing better

Most strains of mycoplasma are sensitive to of particular group of antibiotics.

Antibiotics commonly administered to prevent and control mycoplasma belong to the macrolides group. It has been regularly used to reduce egg transmission and prevent or control respiratory disease in birds.

An effective antibiotic medication to control mycoplasma in multi-age farms requires a monthly treatment to keep mycoplasma at low levels, since infected birds will carry it for life. When the mycoplasma field challenge is lower, the therapy can be carried out every 2 to 3 months.

Zamityl Soluble: One that’s right for your flock

Zamityl Soluble (Tylvalosin), is a new broad-spectrum, third-generation veterinary macrolide antibiotic, that inhibits the synthesis of bacterial protein and the growth of susceptible bacteria.

Zamityl Soluble is liposoluble and has a great capacity to penetrate cell membranes. It can pass through the cell membrane and accumulate in the cytosol.

Zamityl Soluble shows excellent pharmacological properties and high levels of antibacterial activity and plasma concentration. These features make Zamityl Soluble a reliable alternative against susceptible bacteria in the veterinary field.

Zamityl Soluble is a highly effective, water soluble form of tylvalosin, an antimicrobial for use in poultry to control respiratory and enteric diseases | Zamira Australia

Zamityl Soluble showed good efficacy against:

  • Mycoplasma gallisepticum 
  • Mycoplasma synoviae
  • Clostridium spp.
  • Ornithobacterium rhinotracheale

Zamityl Soluble is used in the prevention and treatment of poultry diseases:

  • Chronic Respiratory Disease (CRD)
  • Avian Mycoplasmosis
  • Clostridiosis
  • Ornithobacterium Infection

In addition to its direct antimicrobial effect, Tylvalosin exhibits anti-oxidative and anti-inflammatory activity. Tylvalosin administration significantly decreased tissue injury and reduced the inflammatory cells recruitment and activation.

 This contributed to the improvement of:

  • average daily weight gain
  • average daily feed consumption
  • overall weight gain
  • feed conversion efficiency
  • greater uniformity
  • less rejects
  • more consistent processing weights
  • optimal egg production and eggshell quality

Zamira is an Australian animal health company with a mission to improve the health, wellbeing and productivity of animals across the world. Read more about us here.

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