An Overview of Syngamus Trachea of Poultry in Ethiopia

Girma W, Rebuma T and Negasa T

Published on: 2024-05-08

Abstract

Many different bird species are infected with the strongylid nematode Syngamus trachea, also known as the tracheal worm, which is a member of the Syngamidae family. The parasite is also called as a redworm or gapeworm because of its vivid red color and the fact that those who are badly afflicted usually adopt a gaping-beak position. The strongylid nematode Syngamus trachea, which infects the respiratory tract of numerous bird species worldwide, is the cause of the disease syngamosis. Many different bird orders seem to be affected by the parasite, which can sometimes be lethal, especially in young birds. All domestic birds raised for human food production (meat and eggs), such as guinea hens, turkeys, ducks, geese, ostriches, doves, and pigeons, are considered poultry. While geese and turkey are extremely uncommon in Ethiopia, ostriches, ducks, guinea fowls, doves, and pigeons can be found there in the wild. The abundance of worms that backyard chickens typically have in their digestive tracts causes stress to the animal and impairs its capacity to turn grain into proteins. Obtaining productive and versatile chicken breeds is still one of the biggest obstacles to raising the poultry production industry's economic share. Chickens are exposed to specific parasite eggs and larvae from ingested soils and insects as part of the backyard scavenging production system. Rural free-range chickens are frequently infected with helminth infections, which can even cause subclinical illnesses in small numbers. The drug ivermectin is often used to control gapeworm infection in poultry. Therefore, preventive measures help in reducing the spread of the disease.

Keywords

Gapworm; Syngamus trachea; Poultry; Ethiopia

Introduction

Syngamiasis is the infection caused by the nematode worm Syngamus trachea. S. trachea is a nematode affecting the respiratory system of a variety of domestic and wild avian species [1]. Syngamus trachea is also called “red worm”, “forked worms” or “gape worms” because of their obvious colour, males joined to the female in permanent copulation and clinical manifestation of gasping respectively [2]. By eating one or more of these intermediate hosts containing an egg or larvae of S. trachea, the bird can become infected, the larva makes its way from the stomach of the bird, through the blood vascular system to the lungs or trachea, where it then grows into an adult and finds a mate to copulate with, the prepatent period in chickens (Gallus gallus) is 12-17 days and the adults can live 2-4 months.

The adult male and female become permanently joined in a “Y” form following copulation. The parasites cause mechanical damage, anemia, inflammation, and excessive mucus production because they feed on the blood in the trachea tissue. The symptoms that infected birds may experience include head shaking, wheezing, and gasping. In addition to impairing food intake, this pain may result in death when paired with blood loss (Atkinson et al., 2008). Gross observations associated with syngamiasis included the recovery of gapeworms, emaciation and pale carcasses, nodules, inflammation, congestion, and bloody exudates in the trachea. Under a microscope, S. trachea infections in birds have been linked to pronounced inflammatory reactions, leucocyte infiltrations into the mucosa, sporadically large cells, and fibrosis surrounding nodular lesions [3,4]. The main issue facing emerging nations like Ethiopia is parasitic infection in chicken, which causes the nation to lose money. Domestic poultry are more likely to become infected because of poor management techniques, undernourishment, a lack of veterinary oversight, and the intricate life cycle of the parasites. The chicken infected with parasites exhibit stunted growth, decreased egg output, decreased weight increase, and severe haemoglobin depression [5]. Consequently, this paper's primary goal was:

To summarize the current status and availability of documents on the prevalence, and risk factors of Syngamus trachea in Ethiopia.

Morphology

A nematode called Syngamus trachea affects birds' respiratory systems. Due to their striking color, the males' persistent copulation with the female, and their clinical gasping manifestation, they are also known as "red worms," "forked worms," or "gape worms" [2]. The parasites, which are sometimes found in the lungs or bronchi of some birds, are known as red worms because they are brilliant red in color when they are young. Compared to the male (2–6 mm), the female (5–20 mm) is longer. Forked worms, or persistent copulation, are formed when men and females are connected together [6]. With six to ten tiny teeth at the base of the cup-shaped buccal capsule, the mouth aperture is large and devoid of leaf crowns. The rays and spicules of the male bursa are short and robust. Eggs are thin-shelled, oval, operculated at both ends, and discharged in a 16-celled stage. They measure 70–100x43–46µm [7].

Epidemiology

In soil, eggs can live for up to nine months, and in earthworms or other transport hosts, L3 can live for years. Temperature and relative humidity had a substantial and positive relationship with larval abundance [8]. In breeding and rearing facilities with outdoor pens—such as those used for pheasant breeding disease is most commonly observed. Eggs can start an infection, and wild birds like rocks and blackbirds can spread it to earthworms as well. In turkeys housed in straw yards, heavy loads can happen. On the other hand, they might be harmful disease spreaders that infect other birds. The parasite primarily affects hen-chicks, goslings, and game birds raised artificially, particularly pheasants [9].

Syngamus trachea most severely affects young birds, particularly game chicks and turkey poultries. Guinea birds of any age are rarely afflicted, and adult hens are typically not sick. Because they can become infected at any age and because some people believe that turkeys are S. trachea's natural hosts, adults frequently act as carriers of the parasite [10]. Pheasants seem to be particularly vulnerable to diseases that cause significant death rates during outbreaks. Suffocation results nearly immediately from the worms' fast growth obstructing the trachea's lumen. The most vulnerable to infection are baby chicks, turkey poultry, and pheasant chicks. Compared to young chickens, turkey poults typically exhibit earlier gapeworm symptoms and start to die sooner after infection [11].

Life Cycle

The gapeworm's life cycle is unique in that it can successfully spread from bird to bird through direct ingestion of infective larvae or embryonated eggs, or indirectly through the ingestion of earthworms that have free or encysted gapeworm larvae that they have acquired by feeding on contaminated soil [12]. The worms' eggs are typically given out in the feces after the host coughs them up and swallows them. Under ideal temperature and moisture circumstances, the infectious larvae (L3) need around three days to develop inside the eggs; but, under field conditions, they often take one to two weeks [13]. The larva has two moults within the egg; it has a short, pointed tail, a relatively lengthy oesophagus, and it keeps the cuticle from the previous stage as a sheath. Third-stage infectious larvae (L3) develop inside the eggs during the preparasitic phase, after which they may hatch. The eggs are coughed up, ingested, and eventually expelled in the feces when the female S. trachea lays her eggs in the trachea of an infected bird [3].

Earthworms are hosts that facilitate transfer (paratenic); the researcher has demonstrated that larvae housed in earthworm muscles can sustain their viability for over three years. One of three mechanisms can cause infection: either the L3 in the egg is consumed, or the hatched L3 is consumed, or the L3 is consumed by the ingestion of a transport (earthworms, snails, slugs, flies, beetles, and other arthropods, where larvae encysted) that contains the L3 [14]. The L3 enter the lungs through the final host's intestine and most likely go there via blood because they are discovered in the alveoli 4-6 hours after infection. Within five days, the two parasitic moults occur in the lungs, by which time the parasites have grown to a length of 1.0–2.00 mm [15].

Pathogenesis

When larvae and adults migrate through the lungs, it can cause severe pneumonia in young birds, which is the most severe effect [2]. Where the worms connect to the trachea and bronchi, lymphoid nodules develop. It seems that adult worms consume blood as well. Hemorrhagic tracheitis and bronchitis are caused by worms in the trachea and bronchi, which also produce a lot of mucus, clog the airways, and, in extreme situations, asphyxiate the patient [16]. When lung infections are severe, lung migration can result in ecchymoses, oedema, lobar pneumonia, and even mortality. Adult worms cling to the mucosa in the trachea and feed on blood, causing catarrhal hemorrhagic tracheitis and copious mucus secretion [3].

The mucus obstructing the airways can make breathing difficult. When the males bury their anterior ends deeply in the turkeys' tracheal wall, nodules grow. The male worm is attached to the tracheal wall for the duration of its life, taking the form of lesions [2]. The female worms seem to sporadically split off and reunite in an attempt to obtain more food. The trachea of pheasants and turkeys typically has lesions, but the tracheas of young chickens and guinea fowl almost never have lesions [17].

Clinical Signs

While adult worms and excess mucus in the trachea result in signals of asphyxia and suffocating with the bird gasping for air, pneumonia during the prepatent phase may elicit signs of dyspnea and sadness [2]. If not, we can state that diseased birds will gasp for air due to worms and mucus obstructing their trachea and bronchi. A sick bird may frequently shake its head violently and cough to try to clear the obstruction from its trachea and restart regular breathing. The hallmark symptoms of "gapes" are hypoxia and dyspnea, which come on in fits due to mucus buildup in the trachea [5].

The bird makes gaping gestures, extends its neck, shakes and tosses its head around, and may even cough. They make a hissing sound as they extend their necks, open their mouths, and beg for air. The term "gapeworm" is commonly used to refer to Syngamus trachea because of its "gaping" posture Asphyxia during one of these attacks or the parasite's increasing emaciation, anemia, and weakening are the causes of death. The aforementioned clinical symptoms initially manifest one to two weeks following infection [2].

Diagnosis

Typically, a diagnosis is based on the traditional clinical indicators of "gaping." At necropsy, subclinical infections with few worms can be verified by locating copulating worms in the trachea and the distinctive eggs in the infected birds' feces. The mucosal membrane is highly irritated and inflamed when the tracheas of diseased birds are examined [18]. This irritation to the mucous lining appears to be the cause of coughing. When paired with gapeworm, sneezing and nasal discharges are significantly less common than with CRD. In addition, a phlegmy, congested sound in the chest is typically indicative of CRD. As opposed to the gurgling or rattling sound the gapeworm makes from the throat or trachea, because they affect the upper respiratory tract, gapeworm infestations have similar symptoms to chicken respiratory disease; the two are frequently confused [19].

Treatment and Prevention

The intake of eggs that diseased birds cough up or have in their feces is how gapeworms spread. Consequently, depending on the anthelmintic to be employed, it is imperative to treat birds for gapeworm twice at intervals of one to two weeks. It's interesting to note that the birds' adult worm infection will be destroyed by the first treatment, and any worms that have hatched from eggs or been consumed since then would be eliminated by the second treatment. It is not advisable to raise young birds alongside adults, particularly turkeys. Additionally, to avoid spreading infection, it is best to keep runs or yards dry and avoid interacting with wild birds. Severe out breaks of gapeworm infection are less likely to occur if the birds are not kept for long periods on the same ground [20].

Conclusion and Recommendation

Syngamus trachea is a parasitic nematode of thin, red worm, known as a gapeworm which lives in the trachea, and sometimes the bronchi or lungs of certain birds. They can affect chickens but are common in turkeys, waterfowl (ducks and geese) and game birds. The resulting disease, known as “gape” or “the gapes”, occurs when the worms clog and obstruct the airways. The worms are also known as “red worms” or “forked worms” due to their red color and the permanent procreative conjunction of males and females. When birds feed on earthworms as an intermediary host, gapeworms can induce respiratory discomfort. As a result of adult worms and extra mucus in the trachea, pneumonia during the prepatent period can cause symptoms of dyspnea and despondency, while asphyxia and suffocation with the bird struggling for air are the result of pneumonia. Large bipolar nematode ova in faeces and blood-red nematodes in the trachea are diagnostic indicators. Standard avian doses of ivermectin and benimidazole anthelmintics work well, but illness prevention also helps to stop the disease from spreading. Thus, in light of the foregoing result, I suggest the following points:

It is not advisable to raise young chickens with adults. Additionally, to avoid spreading infection, runs or yards should be maintained dry and contact with wild birds should be avoided.
The likelihood of severe outbreaks of gapeworm infection is reduced when birds are not housed on the same surface for extended periods of time.
By implement a regular deworming program

Acknowledgments

The authors are thanking full to Mr. Wondesen Girma Lema and Dr. Tolesa Negasa for going through the manuscript for computer help and providing facilities to review in the field of Syngamus trachea of poultry.

Author’s contributions

All authors have made substantial, direct, and intellectual contributions to the work.

Conflict of interest

The authors declare that they have no conflict of interest.

Financial support

No financial support received from any organization.

International Journal of Veterinary Science and Medical Diagnosis