Are Bacteria Invertebrates? 3 Facts You Should Know


The bacteria are small free living, only seen under microscope. They may be beneficial or pathogenic in nature. In this article, we will illustrate complete information about are bacteria invertebrates.

All the living matter grouped depending on their common characteristics. The animal kingdom is categorized into vertebrates and invertebrates. The bacteria are single celled and not visible. There are many bacteria that infect the invertebrates known as bacterial pathogen of invertebrates.

Invertebrates are the cold blooded animal groups that have no possess or have vertebral column which is derived from the notochord. In Greek times, Aristotle divided things into plants and animals. But at the present, we categorized them in 6 kingdoms including: Animals, Plants, Fungi, Protist, Eubacteria and Archaebacteria.

How are bacteria Invertebrates?

Bacteria that infect the invertebrate and cause pathogenicity are bacterial pathogen of invertebrates. In most the diseases, the invertebrates act as an important factor for transmitting or spreading the diseases. The bacteria complete its life cycle with the help of invertebrates.

Now a days, there are many bacteria used as microbial insecticidal. They are known as Entomopathogenic bacteria. In the microbial insecticidal process, the bacteria release its toxin that act as insecticides. These bacteria enter into the host via ingestion, produce toxins and other pathogenic factors that will disrupt the midgut epithelium of host cell. Due to disruption of epithelial cell, allow access to nutrient rich epithelium, there proliferate to cause septicemia and death of invertebrate host.

Many invertebrates are common vector of diseases. The vector is defined as an organism which spreads diseases from one host to another. Invertebrates spreads bacterial pathogen by the two mechanisms actively or passively.

Biological vectors such as mosquitoes and ticks may carry bacteria that multiply within their bodies, reproduce and delivered to the new hosts invertebrate, usually by biting. Mechanical vectors are those organisms such as flies, mosquitoes can pick up infectious agents from outside of their bodies mainly from surrounding and transmit them through physical contact.

Are all bacteria Invertebrates ?

The bacteria can infect both invertebrates and vertebrates. They can cause pathogenicity to both kind of animals. In most the cases, bacteria serve the invertebrates as a vector to complete its life cycle, do not infect the invertebrate but infect the second animal. In vertebrate, they mainly cause infectious diseases.

The bacterial-animal interaction is mainly from predation to obligate and beneficial symbiosis. The major activities of animal-bacterial interactions are nutrition, cell adhesion, recognition and signaling.

The interaction between animals and bacteria are reflected by their genomes. Due to modern genome sequencing techniques, revels that many animal genes are homologs to bacterial genes. In a case study showed that about 37% of the ~23,000 human genes have homologs( similar features) in the bacteria and Archaebacteria.

Examples of invertebrates infected by bacteria

Borrelia burgdorferi

The bacteria responsible to cause the Lyme diseases or Lyme borreliosis. It is the vector-borne diseases, spreads by ticks in the genus Ixodes. The most common infection sign is erythema migrans (an expanding red rash) appears at the tick bite site.

Rickettsia prowazekii

The bacteria are responsible for the epidemic typhus (also known as typhus fever). It is spread by body lice. Epidemic typhus usually outbreaks when poor sanitary conditions and crowding occurred. Prevention is achieved by avoiding its vector contact.

Orientia tsutsugamushi

In Japanese tsutsuga meaning is “illness” and mushi meaning “insects”. It is mite borne bacteria responsible for the scrub typhus in humans. It belongs to the family Rickettsiaceae. It is the intracellular and obligate bacteria of mites. A scar like scab is good indicator of infection.

Rickettsia typhi

The bacteria Is obligate intracellular (strictly inside the host cell), aerobic( survive only in presence of oxygen) and rod shaped gram negative bacteria. R. typhi is zoonotic (spreads in animals) agent that cause the diseases murine typhus. It is flea borne diseases. The symptoms of diseases are non-specific mild fevers, headaches, pains and rashes.

Rickettsia akari

It the mite-borne bacteria that is responsible for the infectious illness Rickettsial . The first symptoms are bump at the bite site later on from black, crusty scab.

Rickettsia conorii

The bacteria are responsible for the disease Boutonneuse fever (also known a Mediterranean spotted fever, Kenya tick typhus, Indian tick typhus, Marseilles fever or Astrakhan fever). It is spreaded by dog tick Rhipicephalus sanguineus. The name of diseases after the word boutonneuse means “spotty” in French due to its popular skin-rash features.

Rickettsia africae

It is the bacteria which is causative agent of the diseases African tick bite fever (ATBF). The infection is spreads by the tick bite. Symptoms may include fever, headaches, rash and muscle pain. The bite site, a typical red skin sore with a dark center.

Rickettsia ricketsii

It is caused bacteria diseases Rocky mountain spotted fever (RMSF). The bacteria spread by the ticks. The typhus fever typically begins with fever and headache, later on rash developed. The small bleeding starts with wrists and ankles.

Are bacteria invertebrate
Rickettsia rickettsii from Wikipedia

Francisella tularensis

The bacteria cause the diseases Tularemia (also called rabbit fever, deer fly fever, Ohara’s fever or pahvant valley plague). The diseases spread by ticks, deer flies and contact with infected animals. The symptoms include fever, skin ulcer, large lymph nodes.

Yersinia pestis

The bacteria caused the disease Plague. Human get infected plague after bitten by rodent flea, carry the plague bacteria. The most common plagues are bubonic, pneumonic and septicemic.

Borrelia recurrentis

It is human restricted pathogen (infect only humans) that caused the diseases Louse-borne relapsing fever (LBRF).the pathogen is spreads by body louse Pediculus humanus humanus.

Salmonella typhi

The bacteria Salmonella serotype typhi bacteria known to cause typhoid fever also named as typhoid. Sometimes it spreads by common house flies. The symptoms starts from fever low and increases daily, headache, weakness, dry cough stomach pain, diarrhea.

Vibrio cholerae

The bacteria cause an acute diarrheal illness known as Cholera, mainly infected intestine. House flies are the primary agent in transmitting the diseases. It is spreads by infected water and food by the cholerae bacteria.

Shigella dynenteriae

The bacteria responsible to cause shigellosis (bacillary dysentery). The house flies are main vector. Symptoms includes colitis, malnutrition, rectal prolapse, and central nervous systems problems.

Escherichia coli

Although most strains if E.coli are harmless , others can make human sick. Some kinds of bacteria can cause diarrhea, while other cause urinary tract infections, pneumonia, respiratory illness and other illness. Symptoms of Shiga toxin producing E. coli are severe stomach pain, vomiting and often bloody diarrhea.

Bacillus thuringiensis israelensis

It is the group of bacteria used as biological control agents for certain dipterans’ larvae. Bti produces toxin which kills many invertebrates species like blackflies, mosquitoes and fungus gnats. They are target specific, do not kill non-targeted species of pests.

Bacillus thuringiensis kurstaki

It is the group of bacteria used as biological control agent against lepidopterans. During sporulation, Btk produces a crystal protein that is lethal to lepidopterans larvae. It is target specific bacteria.

Bacillus thuringiensis morrison

It is natural predator for the golden-tailed moth, silkworm.

Lysinibacillus sphaericus

It has larvicide effects of some strains against two mosquitoes Culex and Anopheles. The bacteria in its vegetative stage are also effective against Aedes aegypti larvae, responsible for yellow fever and dengue.

Serratia entomophila

The strain of S. entomophila AB2 spread from Heliothis sp. (Lepidoptera) having both fungicidal and nutrient

solubilizing capacity.

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