Overview

Our health can be affected by many things in our lives. One of the most common things that we encounter is infections. Infections can come in different shapes and forms; they can be mild, such as the common cold, or be as severe as tuberculosis.¹ Infections can also be either viral, fungal, or bacterial.² However, in this article we will focus on the bacterial side of things.

So how does an infection occur? It occurs when a pathogen enters our bodies (through various routes like ingestion, inhalation, or through the skin) and causes an illness.³ It is important to know the different causes of each illness to give the appropriate treatment and medical care; for example, mild illnesses can be treated with simple rest and supportive care, while more serious infections will require antibiotic therapy and any other considerations to avoid complications.^4,5 

In this article, we will focus on anthrax and compare it to other bacterial infections. So, what is anthrax? It is a zoonotic illness that has affected animals and humans for centuries, so much so that it was even considered as a bioweapon.⁶ It is a bacterial infection that affects livestock and can be transmitted to humans through contact with an infected animal or contaminated animal products.³ 

Overview of anthrax

Anthrax is an infection caused by the bacteria Bacillus anthracis, which is a rod-shaped and non-motile bacterium which exists in two forms: 1. biologically active vegetative state and 2. biologically inert spore form.⁷ The first form is the one responsible for the illness and when the animal dies, this vegetative form becomes inert and forms a spore.⁷ These spores remain viable for a very long period of time and are resistant to environmental conditions.⁷ They are found in the soil which is considered the main reservoir for herbivores (both wild and domesticated).⁷

There are multiple routes of transmission for anthrax, and they include:³

• Cutaneous: this usually occurs when anthrax spores are introduced into a cut or wound while someone is working with infected animals or contaminated animal products such as hair or wool. This form is considered the most common and also the least dangerous
• Injection: this type is seen among drug users who use heroin-injection. It is a similar form to the cutaneous one, but causes an infection deeper under the skin or in the muscle where the drug was administered/injected
• Inhalation: This form occurs when an individual inhales anthrax spores. This form is the deadliest and occurs in people that inhale anthrax spores through occupations where they are in contact with an infected herbivore or contaminated animal products such as wool mills, slaughterhouses or tanneries
• Gastrointestinal: this form occurs when spores are eaten through raw or undercooked meat of an infected animal

Some people tend to be at more risk than others for this infection and this includes:⁷

• Living in an endemic area
• Agricultural occupations such as butchers, dairy workers, veterinarians, herdsmen etc
• Industrial occupations such as drum makers, shoemakers, carpet weavers, wool spinners
• Illegal drug use leading to a risk of injecting contaminated material

Symptoms³

Symptoms of anthrax vary based on the type and can be seen either from the first day or up to two months after the initial exposure.

Cutaneous³

• Itchy small blisters or bumps
• Painless sore that appears after the bumps go down. It is commonly seen on the face, neck, arms, or hands and has a black centre
•  In terms of injection anthrax, there will be infected sores/abscesses deep under the skin or muscle at the administration/injection area

Inhalation³

• Fever, chills and heavy sweats
• Chest pain
• Cough or shortness of breath
• Confusion
• Dizziness
• Nausea/vomiting
• Stomach pain
• Headache and body aches
• Extreme fatigue

Gastrointestinal³

• Fever and chills
• Sore throat and painful swallowing
• Swelling of the neck/neck glands
• Nausea, vomiting and diarrhoea
• Bloody vomiting and diarrhoea 
• Headache
• Stomach-ache
• Fainting
• Red face and eyes

Overview of other bacterial infections

Other bacterial agents can be culprits of other diseases, and some of them include staphylococcus, streptococcus, E. coli and salmonella.^8,9,10,11

Staphylococcus

It is a common bacteria that is found on the skin and mucous membranes, but sometimes it can cause infections and illness.¹² The most important one in human disease is Staphylococcus aureus.¹² Other staphylococci such as Staphylococcus epidermidis are usually present on the skin as normal flora.¹²

S. aureus can cause skin infections and it also releases toxins that can lead to food poisoning or toxic shock syndrome.¹³ Staph bacteria can cause infection if it gets inside the skin through a cut or a bite, and it can spread to others through close skin contact, sharing towels/toothbrushes or less commonly through droplets in sneezes/coughs.⁸

Streptococcus

Streptococcus bacteria, depending on the type, can cause illness in humans such as strep throat due to Streptococcus pyogenes.¹⁴ Streptococcus pyogenes can also be known as group A streptococcus or strep A.¹⁴ Strep throat is common, especially among children between the ages of 5-15, but it can also affect older teens and adults.¹⁵ About 30% of sore throats in children are due to strep A, along with tonsillitis, impetigo and cellulitis.^14,15 

While symptoms vary based on the type of infection, strep A can be carried without any symptoms in the respiratory tract or on the skin.¹⁴ However, in some rare cases, strep A can pose a fatal infection which can give rise to complications.¹⁴

Strep A is spread from person to person through respiratory droplets (from coughs and sneezes), contact with the bacteria on the skin or contaminated surfaces.¹⁴

E. coli

E. coli, or Escherichia coli, are bacteria that are found in many places such as the environment, food, water and even the intestines of animals and humans.¹⁰ The majority of them are harmless and are part of a healthy gut.¹⁰ Additionally, it can help us digest food, produce vitamins and even protect us from harmful pathogens.¹⁰

However, sometimes infections from E. coli can happen and can cause diarrhoea, urinary tract infections, pneumonia, sepsis and others.¹⁰ Some individuals are more at risk than others such as children younger than 5 years of age, elderly (≥65 years), people with weak immune systems and international travellers.¹⁰

Infections with E. coli can happen via contaminated food or water or when coming in contact with the bacteria from the environment, animals/people.¹⁰

Salmonella

Salmonella infections are caused by salmonella bacteria.¹¹ There are various types of salmonella bacteria and they are passed from the faeces of humans/animals to other humans/animals.¹¹ Contaminated food such as eggs, milk, beef, poultry or seafood can have salmonella in it and it's usually from an animal origin.¹¹ However, all foods along with unwashed fruits/vegetables can become contaminated.¹¹

One type of salmonella that infects only humans is Salmonella typhi and it is transmitted from human to human through contaminated food or water.¹¹ If left untreated, it can lead to a life-threatening infection known as typhoid fever.¹¹

Everyone can get salmonella, however, certain factors can increase the risk such as eating raw or undercooked eggs, beef, poultry or eating unwashed fresh fruits and vegetables, handling animals or pets (like snakes, lizards or turtles), travelling to less developed areas of the globe, or taking medication/having a condition that decreases stomach acidity.¹¹

Symptoms 

There are different symptoms that arise from different infections, and in this section, we will summarise each.

Staphylococcus

• Painful red bump or lump on the skin⁸
• Hot, red, swollen skin⁸
• Sore and red eyelids/eyes⁸
• Folliculitis¹²
• Impetigo¹²
• Toxic shock syndrome¹²

Streptococcus A⁹

• Flu-like symptoms
• Sore throat
• Scarlet fever
• Scabs and sores
• Cellulitis
• Severe muscle ache
• Nausea, vomiting
• In rare cases, strep A can cause complications that can lead to kidney disease, acute rheumatic fever that can lead to skin, joint, heart and brain problems¹⁴

E. coli¹⁶

• Diarrhoea that can be bloody
• Stomach cramps
• Vomiting
• Fever
• Haemolytic uremic syndrome can lead to kidney failure, permanent health issues and possibly death

Salmonella¹¹

• Fever and chills
• Diarrhoea
• Cramps
• Headache
• Nausea and vomiting

Therapy/treatment

Treatment can vary between infections and that includes anthrax and other bacterial infections. In this section, the different treatments are highlighted.

Anthrax

• Antibiotics like ciprofloxacin and doxycycline¹⁷
• Antitoxins are used to treat patients that have activated spores that release the toxin. This treatment should be given alongside other methods such as antibiotics¹⁷
• Serious cases would require hospitalisation with aggressive treatment and supportive care. This includes continuous fluid drainage and mechanical ventilation¹⁷
• Vaccination can be an option in high-risk population¹⁸

Staphylococcus

• Antibiotics like amoxicillin, clindamycin or cephalexin¹²
• Drainage of pus¹²
• Surgical removal of dead tissue¹²
• Treating underlying skin conditions that make it more susceptible to infection like atopic eczema¹²

Streptococcus A

• Antibiotics like penicillin or amoxicillin¹⁹
• Supportive care and resting at home⁹

E. coli⁴

• Supportive care (e.g. hydration and resting at home)
•  Avoid the use of antibiotics as it can increase the risk of complications
• Avoid the use of anti-diarrhoea medications, like Imodium, as it can extend the exposure to the bacterial toxin

Salmonella¹¹

• Treatment will vary based on the individual symptoms, age and general health
• Gastrointestinal salmonella infections remain between 4-7 days and usually require no treatment aside from rehydration
• Antibiotics are prescribed in certain conditions such as having a weak immune system, severe illness or in cases where the infection can spread from the intestines to the blood

Summary

Anthrax is a serious infection that can lead to severe consequences if left untreated. So much so that it is considered a bioweapon. However, it is still treatable. Compared to other biological infections, it would require more extensive care. It is important for us to understand and identify, with the help of healthcare professionals, what is causing our symptoms and give the appropriate treatment and care.