An Overview of Furunculosis

Faeze Izadi; Mohammad Forouhar Vajargah

doi:10.37871/jbres1507

ISSN: 2766-2276

Medicine Group . 2022 June 30;3(6):738-741. doi: 10.37871/jbres1507.

Subject area(s)

Dermatology

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Review Article

An Overview of Furunculosis

Faeze Izadi¹ and Mohammad Forouhar Vajargah^2*

¹Student in General Veterinary Medicine, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, Iran
²PhD of Aquatic Ecology, Faculty of Natural Resources, University of Guilan, Sowmehsara, Iran

*Corresponding author: Mohammad Forouhar Vajargah, PhD of Aquatic Ecology, Faculty of Natural Resources, University of Guilan, Sowmehsara, Iran E-mail:

Received: 23 June 2022 | Accepted: 28 June 2022 | Published: 30 June 2022

How to cite this article: Izadi F, Vajargah MF. An Overview of Furunculosis. J Biomed Res Environ Sci. 2022 June 30; 3(6): 738-741. doi: 10.37871/jbres1507, Article ID: jbres1507

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Abstract

The aquaculture industry is currently growing faster than other sectors of human protein production. However, every year, diseases inflict irreparable damage on this growing industry, which inevitably uses antibiotics. In the last two decades, vaccination as a preventive method against various bacterial pathogens in the aquatic industry Cultivation known and has reduced the use of antibiotics. Fish diseases can be caused by several factors, one of which is bacteria. Furunculosis, the most destructive bacterial disease of fish, is now almost distributed worldwide. Furunculosis is a debilitating and deadly disease that affects numerous species of breeding fishes.

Introduction

The aquaculture industry is currently growing faster than other sectors of human protein production [1].The increasing diversity of fish species in the aquaculture industry provides a moral opportunity for disease interactions between species that become infected- Bacterial infection- is the main factor in reducing production [1]. Over the past 20 years, vaccination as a preventive method against various bacterial pathogens in the aquatic industry Cultivation known and has reduced the use of antibiotics [2,3].

It is a debilitating and deadly disease that affects numerous species of breeding fishes, including salmon, finfish, and carp [4]. This disease, potentially the most destructive bacterial disease of fish, is now almost distributed worldwide [5]. The disease was first described at a fish farm in 1981 in Germany. Today, vaccination is the key light preventive measure against furunculosis of salmon in Europe, North America, and Chile. The development of the furunculosis vaccine has significantly reduced the utilization of antibiotics in salmon breeding. The first effective vaccine against atypical furunculosis was licensed in Iceland in 1881 [1]. Furunculosis is a complex disease that takes many forms depending on health, age, fish species, and environmental conditions, especially temperature [6]. Disease occurs through contact with infected fish or exposure to water contaminated, salmonicida subsp, can cause disease so Healthy people should be careful when new fish arrive and while exporting aquaculture products to prevent population contamination [7]. Bacteria which include two groups of gram-positive and gram-negative are among the factors that cause various diseases in fish. Here are some brief examples of each.

Gram-negative bacteria

1) Aeromonas

2) Flavobacterium columnare (The causative agent of clomonaris diseases)

3) (Edwardsiella sp) Edwardian sepsis

This pathogen was isolated for the first time from a canal catfish. It often found in waters contaminated with organic matters [8].

4) Vibrio sp (The cause of Vibriosis)

Vibrio is a gram-negative pathogen and beheld in marine fish but it can be seen in freshwater fish as well. It has been reported that about 13 species of that can cause the disease. The clinical signs of this disease are similar to the symptoms of fish infected by Aeromonas salmonicida. Some call it Vibriosis, it is called saline water furunculosis [9].

Gram-positive bacteria

1) Streptococcus sp (The cause of Streptococcus disease)

Streptococcus is a common disease in breed and wild fish [8].

2) (Mycobacterium sp) Mycobacteriosis

Clinical signs of mycobacteriosis include exophthalmos, alopecia, and anorexia. Cutaneous complications include discoloration of the skin and Scales are nodules, ulcers, fin rot, and respiratory disorders. A large number of -Granulomas Mycobacteriosis- has been observed in different parts of the fish body in which a large number of bacteria are present [8].

3) Nocardiosis (Nocardia asteroides)

Nocardiosis comes from Actinmycete of the genus Nocardia in freshwater and saltwater fish [8].

The causative agent of Fronculosis

Aeromonas salmonicida subsp. bacteria is the causative agent of furunculosis which is a systemic fish disease belonging to the salmonid family. It is a pervasive disease that affects the aquaculture industry worldwide and is known for high mortality and morbidity [8]. This disease is a debilitating and fatal disease that affects several bred species of fishes, including salmon, valves, and carp [9]. This disease, which potentially is the most destructive bacterial disease of fish, is now distributed almost worldwide. Furunculosis1981 was described from a fish farm in Germany [8]. A. salmonicida subsp. salmonicida is a gram-negative bacterium that is ubiquitous. This bacterium can cause sepsis Hemorrhagic, olstrithological lesions, sharp bleeding, and death [10]. There are five subspecies described by A. salmonicida:subsp, subsp. achromogens, subsp. salmonicida subsp, masoucida. Smithia and subsp. Pectinolitica [11,12] Achromogenes that cause A. Atypical furunculosis, a systemic disease in many fish species, is recently known by many researchers to form a homogeneous group of strains. Even though atypical infections are the systemic disease of salmonicida, they can cause an Ulcerative disease with surface pathological lesions and unlike furoncolysis [1].

Let alone it's a systemic disease, ental organs can be sampled for pure culture. When the disease included Skin wounds, bacterial samples should be taken of recently created wounds [1]. Bred fishes in the aquaculture industry are forced by more stress than fishes in nature. High levels of ambient organic matter, low dissolved oxygen levels, consolidation of fishes, increase their proximity to infections [13]. In the antibiotic sensitivity test, all isolates of A. sobria showed resistance to amoxicillin and ampicillin. Six isolates A. sobria and two isolates of A. salmonicida showed resistance to oxytetracycline [10]. Most of the diseases that causes infection are gram-negative bacteria, including Aeromonas, Edwardian, Faulksia bacteria, Pseudomonas, Mycobacterium, Vibrio and Citrobacter [8]. Bacteria can be the first cause or secondary cause of the disease. Bacteria can easily live everywhere [8]. The virulence of this bacterium requires a plethora of characteristics that allow the bacteria to develop the disease in the host, so if the virulence factors of this bacterium overcome the host defense mechanisms, the bacteria can infect the host. Some virulence mechanisms of this bacterium have been known for a long time and others have recently been discovered in the genome of A. salmonicida [14].

The acuity mechanisms of this bacterium include

A layer: Encoded by the vapA gene, it is a complex protein structure associated with Lipopolysaccharides (LPS) on the cell surface [15] and have a quadrilateral structure connected to diazodusulfanilic acid [16]. This hydrophobic protein increases the bacterial level and is responsible for bacterial autoaglutination, sticking to macrophages, and resistance to the cytotoxicity of macrophages [17]. This layer can act as a bacteriophage receptor [18]. While in other cases it can cover phage receptors in the outer membrane [19].

Extracellular molecules: Proteases, lipases, and other extracellular molecules can also be pathogens. Proteases play a role in the proliferation of bacteria and contribute to the spread of the disease by overcoming the host defense system and supplying nutrients from the host [20,21]. Absorption of nutrients from the host can sometimes cause damage such as skin lesions [22]. Salmonicida produces many proteases [23] that these enzymes are considered as the main pathogen by themselves [7].

Type 3 secretion system: This bacterium, like many other gram-negative bacteria, has three types of (TTSS) secretion system [23]. TTSS is a needle-shaped protein complex that allows the transfer of toxins from bacterial cytoplasm to host cell cytoplasm. TTSS can prevent phagocytosis, affect the actin cell skeleton, and prevent signal transmission and cellular communication. It can protect bacteria of phagocytosis dying [24].

Genome characteristics: Reith, et al. [13] obtained information about the genome content of this species of bacteria. A449 genome from a single chromosome (4122 KB) and five Plasmids (pAsa4, pAsa3, pAsa2, pAsa1, and pAsa5) are composed.

Genomic plasticity: Heat has a detrimental effect on the genome of this bacterium, and when A. salmonicida is cultured at a higher temperature of 25°C, layer A disappears [19].

Signs

Furunculosis has taken its name from furuncles or pimples that appear on the skin and muscles of the fish affected by subacute or chronic forms of this disease [25]. In the acute form of this disease, most seen in young salmon, the disease quickly leads to septicemia, which can be seen subsequently, necrotized lesions in the skin, and bleeding in the internal organs. Acute form causes sudden death without clinically evident except lethargy, anorexia, and darkening of skin pigments [7]. The subacute or chronic form of the disease has a slow onset of ailments and low mortality [7,26-30]. These infections are fatal, mostly in cases within two to three days [31,32] about the recessive form of the disease, fish carry the causative agent [33].

Diagnosis and treatment

The faster the disease is diagnosed, the better it can be dealt with [8]. In most cases, it is better to cultivate the bacteria for better diagnosis and treatment and sensitivity tests [8]. Although furunculosis can be diagnosed temporarily from clinical trials, confirmation of diagnosis, and differential diagnosis from other bacterial diseases of fish should be based on isolation and identification of pathogens. It is because the pathogenesis of Furunculosis (and its clinical manifestations) are similar to other diseases of fish with a gram-negative bacterial cause [5].

Bacteremia and septicemia

Bacteremia means the presence of bacteria in the bloodstream and septicemia expressing the presence of bacteria in several parts of the body [8]. Bred fishes in the aquaculture industry are forced by more stress than fishes in nature. High levels of ambient organic matter, low dissolved oxygen levels, consolidation of fishes, increase their proximity to infections [13]. There are two base forms of furunculosis: the acute form, which is the most common and characterized by a general septicemia-type disease that has a short period and causes a high rate of mortality. A subacute or chronic form that despite focal lesions)"furuncles"(is characterized by relatively low mortality in the muscle [5]. The acute form is septicemia: extensive bleeding and necrosis that causes extensive tissue damage and death within a few days [5]. In the subacute and chronic form, focal muscle lesions ("furuncles") that contain large amounts of necrotic muscle, blood, and bacteria, are created. Fish may recover from this form. This form of the disease is detectable even though the dark scarring, where furuncle has improved [5]. Furoncolose is often treated orally with quinolone antibiotics, mainly exolinic acid and flumekin.

Transmission way

Transmission of the disease is probably direct, either through infected fish eaten by other fish or through close contact with them. The exact pathway of bacteria enter into the fish is unknown, however, the existence of abrasions and external parasites biting the infection facilitates [5]. The disease can cause by contacting infected fish or exposure to water contaminated with A. salmonicida subsp. so, healthy people should be careful when entering new fish and while exporting aquaculture products to prevent the population from polluting [7].