Depression in the Animal Kingdom

According to the World Health Organisation, depression is a common mental disorder affecting over 260 million people around the world. It is characterised by a persistent feeling of sadness, lack of pleasure in otherwise rewarding activities, often accompanied with lack of appetite, sleep and concentration and a constant feeling of tiredness. Depression is the result of an imbalance of hormones and chemicals in the brain often occurring during challenging times, but scientists have shown that it also has a genetic component in about 40-50% of the cases.

But, can animals also suffer from this condition? Every so often, animals look lethargic, with an appearance of sadness and lack of interest for activities that they otherwise would enjoy. Can this be the result of alterations on their mental state? If so, what is causing the animals to feel that way and how can help them improve?

By Ricardo Ribas

Whilst animals don’t have the same reasoning capacity as humans and don’t experience the same level of social and psychological complexities, scientists and behaviourists agree that animals can also feel stressed, sad and depressed.

What are the main reasons for depression in animals?

Many factors can trigger alterations in the animal’s mental state. Dogs and cats often develop anxiety and depression as a result of physical illnesses, fears or alterations in the animal’s environment, such as during fluctuations of the owner mood, new pet ownership, relocation to a new home, abandonment or confinement and whilst grieving after a loss of a close human or animal. Despite of being rare in the nature, wild animals can also develop suffer from these conditions, particularly throughout challenging times such changes in the environment, habitat or during death or loss of a close animal.

What are the symptoms in animals?

Researches have shown that mammals, and in particular primates, share anatomic, functional and chemical similarities with human brains, making them the most susceptible species to develop depression. However, since animals are unable to speak and transmit their feelings to humans, makes the diagnosis of these diseases very challenging. To better understand their mental state, scientists base their judgement on the animal’s mood and the changes in their normal behaviour. Primates are perhaps the most transparent of the species and the easiest to illustrate their feelings of sadness based on their facial expressions, but when this not possible, scientists and vets often look for other symptoms, such lethargy, lack of enthusiasm to pleasurable activities, loss of appetite, as well as changes in behaviour and in sleeping patterns. For instance, the majority of the dogs are comfortable when left alone at home for a few hours, whilst others develop obsessive behaviours such as constant barking and crying, repeatedly licking of parts of their body, biting furniture, defecating, urinating or showing changes in their normal behaviour such as aggressiveness, etc. Each animal has its different personality and is very important that the owners understand what is normal or not for each animal. It is also frequent to encounter signs of anxiety and depression in animals kept in captivity, often exhibiting repetitive and compulsory behaviours, such as the constant walking back and forward or in cycles.

Then how can we help the animals through these difficult times?

To start with, it is important to rule out that the changes in the animal’s behaviour are not the result of a simple underlying physical condition or disease. If the animal appears to be suffering from depression-like behaviour, there are a few things the owner can do. Here are some advices:

• Engage with the animal in fun activities, such as games, exercises, etc

• Increase the time spent with the animal and pay more attention to them

• Take your animal for longer walks and exercises

• Incentive the animal to play with other animals

• Limit the time the animal is left alone

• Take time to bond with them

Each animal has a different personality and is essential to understand the reason behind their sadness to better help them. If none of the advices work, consider taking the pet to a behaviourist or to the vet, which can ultimately prescribe antidepressant medications.

Depression can take time but often disappears with some changes in the animal day-to-day life. Nevertheless, it is crucial not to let the disease progress as it can deteriorate the animal’s health and be life threatening.

Large studies are lacking in this field and a lot of research is still necessary to better understand the way the animal feel and how to help them fight the disease. However, many studies agree that animals often help humans improve from depression and that owning a pet can be very beneficial to fight this condition. It is now in our hands to help them too!!

By Ricardo Ribas, veterinary doctor, doctorate in veterinary sciences and scientist in London.

Reference Sources

1. Flint J., Kendler K.S. The genetics of major depression. Neuron. 2014;81:484–503. doi: 10.1016/j.neuron.2014.01.027.

2. Krista Mifflinm. Dogs and Depression. The SprucePets. https://www.thesprucepets.com/do-dogs-get-depression-1112512. Updated 28.05.20. Accessed on August 2020.

3. Depression. World Health Organisation https://www.who.int/health-topics/depression#tab=tab_1

4. Sasha Ingber, Do animals get depressed? National Geographic News, National Geographic. https://www.nationalgeographic.com/news/2012/10/121004-animals-depression-health-science/. Published 06.10.12. Accessed August 2020

5. Tibi Puiu. Can animals get depressed too? ZME Science. https://www.zmescience.com/ecology/animals-ecology/animal-depression/. Published 22.09.16. Accessed August 2020.

Disclaimer

The material, ideas and prevention measures discussed on this article are for informational purposes only. For more information consult a vet or a professional in the area. Whilst every effort is made to make sure the article is accurate at the time of publication, I take no liability for any new developments on the subject as well as any errors or omissions.

Holiday Season: what to do with my pets?

With the holiday season approaching, it is time to decide whether to take your pets with you or to leave them at home. Here are some tips to help you make the right decision.

By Ricardo Ribas

Taking your pet on holiday can turn out to be a very stressful experience for both your furry friend and your family, so it is essential to start planning it well in advance. Before deciding whether to take your furry friend on a trip, make sure you consult your vet to check their health condition and to advise you what is the best way to proceed. For instance, elderly, pregnant and very young animals as well as the ones with underlying health conditions, may require extra care and may be advised against going on longer trips. Bear in mind that some animals get very stressed whist travelling so it is important to take into account both the distance and the mode of transport before deciding whether to take them. Finally, remember to check the weather conditions at your destination to avoid exposing the animals to very hot temperatures and ensure the access to animal-friendly accommodations, restaurants and other attractions such as beaches, etc.

DECISION TAKEN: THE ANIMAL WILL STAY!!

If you decide against taking your pets on holidays, make sure you plan in advance where to leave them. Like humans, each animal has a different personality and can react differently to the same situation. It is important to remember that a separation of the animal from its owner usually causes some degree of anxiety. Some animals respond well to separation, particularly if they stay with acquaintances and in familiar surroundings, whilst others may exhibit behavioural changes such as stopping eating, lethargy, sadness or even aggression. In order to minimize their anxiety, it is important that the you start adapting the animal to the place and the person who will be taking care of them during your absence. Ideally, leave your pet at your home and invite a friend or a family member to stay at your house, but if this is difficult, there are several kennels, hotels or animal sitters that are happy to take care of your pet during your absence. It is important to visit the facility well in advance to examine if it is good enough for your animal. Be aware of the hygiene, size, light, exercise area, food, veterinary assistance, employees, as well as the risk of your animal being infected by any potential diseases. Also remember that many places require an advanced reservation so plan well in advance. If you leave the animal at one of these places, it is a recommended that you bring some of the animal’s toys, as well as their bed or basket and a piece of the owner’s clothing with their scent so that the animal feels more comfortable. Make sure you instruct the carer about the animal’s habits as well as their food requirements. Finally, leave your contact details as well as your vet’s for any eventualities and ask for regular updates whilst you are away.

Never in any circumstances abandon your pet. An animal left without any human protection will feel lonely which can lead to extreme anxiety and psychological disturbances.

THE ANIMAL TRAVELS WITH YOU…

If you decide to take your animal on holidays, it is important to plan the trip well in advance and to choose the safest and most comfortable way of transportation, making the animal’s experience as comfortable as possible.

Travelling by car is usually the best option, but some precautions should be taken. Other easy options include train or boats/ferry where owners are usually allowed to take their pets with them, often with a charge attached to it. It is important to make sure owners prepare their animals for the long trip ahead by taking them for short test drives. During the trip, always carry cold water for the animal and never leave your animal inside the car, on its own, specially in hot weather. Make sure you stop regularly to allow for short exercises and keep in mind that some animals get very stressed on a trip, so avoid feeding them too much beforehand to prevent them from vomiting or having diarrhoea.

Travelling by air requires a lot of planning and should only be considered if there are no other alternatives. If travelling abroad, remember that each country has its own legislation regarding animal arrivals so check in advance with your airline, your vet and the country destination for the specific requirements and regulations. Animals often require to be microchipped and to show their documents confirming they are fit and healthy to travel and to enter the country. Some countries also required a pet-passport and a proof of vaccinations and in some instances quarantine measures may apply. It is also highly recommended to have a pet insurance covering trips abroad in case the animal gets sick whilst in a different country.

Always contact your airline well in advance, making sure you reserve a place for your pet and that you understand the animal transportation conditions. Each airline has its own policies and some flights may not be licensed to carry animals, whilst others may only accept a certain number of animals per flight. In some instances airlines may allow you to take small pets with you inside the plane under the seat, but often animals are required to go in the hold under the plane, generally in pressurised conditions similar to the ones in the cabin. If in the hold, the animal will need to be carried inside a special container or box with an adequate size to allow the animal to sit, stand and rotate inside. Assistance and guide dogs are usually allowed in the cabin and can travel for free, but make sure you inform and confirm this with your airline.

Ahead of your flight, make sure you prepare everything for the animal’s comfort and safety, such as:

• Place an identification tag in the animal collar as well as in the container displaying your name, address at destination and your phone number.

• If the animal is travelling in the hold, make sure the details on their tickets are the same as the ones on your ticket and that the tag attached to the container is correct.

• Feed the animal earlier in the day and make sure they are relieved before putting them in the container. For animals that get very stressed during the trip and often vomit, consider withholding food for a minimum of 2-4 hours before the flight. Ask the vet for some medication to prevent it from happening.

• Make sure you include food and water packs within the container particularly for long flights

• Exercise the animals before the trip to tire them. The use of tranquilizers should be avoided because they affect the way dogs and cats control their body temperature.

• Place their blankets and toys inside the transport container.

• Make sure a container has a secure closure, but that allows for opening in an emergency.

Independent of the way you travel with your pet, always remember to take with you:

• Animal documentation such as the health documents and the vaccination certificates.

• The pet passport if you are travelling abroad

• A lead as well as a collar containing the complete identification.

• The animal’s bed or basket

• Bottle of cold water for the trip

• The animal’s toys, food, plates, poo bags and muzzle (if necessary).

Extra care in the summer:

• Like us, animals can suffer sunstroke, dehydration and sunburn – often on their pads – so walking in the street during peak hours should be avoided.

• Parasites such as fleas and ticks are more common in hot months, so make sure you deworm your animal to avoid discomfort and the possibility of catching infections.

• The beach must also be avoided if possible. Dogs can be vehicles of a worm called Ancylostoma caninum, which spreads through their faeces and can penetrate human skin, causing itching. If you take your dog to the beach, don’t forget to deworm him/her beforehand. Also be careful when taking your dog to the sea as water often penetrates the animal’s ears and can lead to infections, particularly in those animals with droopy ears. Cotton can be used to avoid water from entering. If you decide to take your dog to the beach, protect him/her from the sun to avoid sunburn and always carry a bottle of fresh water. Finally, remember to keep your pet on a lead to prevent them from escaping, becoming lost or bothering others.

Enjoy your holidays and love your pet in all seasons!!!

Ricardo Ribas

Veterinary doctor, doctorate in veterinary sciences and researcher

Reference Sources

1. Bring your pet to the UK: step by step. Gov.uk. https://www.gov.uk/bring-your-pet-to-uk. Accessed June 2020

2. Travelling abroad with dogs. Blue Cross for Pets. https://www.bluecross.org.uk/pet-advice/travelling-abroad-dogs. Accessed June 2020

3. Delaney Ross. How to fly with a pet on a plane. National Geographic. https://www.nationalgeographic.com/travel/features/how-to-fly-with-pet-on-airplane/. Accessed July 2020.

4. Travelling with Your Dog on a Plane. Purina. https://www.purina.co.uk/dogs/behaviour-and-training/travelling-with-your-dog/taking-your-dog-on-the-plane. Accessed July 2020.

Disclaimer

The material, ideas and recommendations discussed on this article are for informational purposes only. For more information consult a vet or a professional in the area. Whilst every effort is made to make sure the article is accurate at the time of publication, I take no liability for any new developments on the subject as well as any errors or omissions.

Animals and the Covid-19 Pandemic

A virus pandemic has struck the world in 2020. Coronavirus disease 2019, or Covid-19, is an infectious respiratory disease firstly identified in Wuhan, China in December 2019 and has since spread to every corner of the world, killing many hundreds of thousands of people. A lot of research is still necessary to understand the disease and the virus that causes it, yet scientists believe it was originated in animals. But what do we know so far about the role of animals in the emergence of this disease and which animal is the most likely to have transmitted the virus to humans? Can animals also be affected by Covid-19 and how can they help us in fighting the disease? Discover some answers for these and other questions in the following article…

By Ricardo Ribas

Image from Fernandozhiminaicela, pixabay.com

Understanding Coronaviruses…

Coronaviruses are a large family of viruses that have existed for over 10,000 years. The name derives from the latin word “corona” that means crown due to the presence of crown-like spikes in the virus surface. Coronaviruses are often responsible for respiratory and intestinal diseases in mammals and birds but symptoms can vary according to the host as well as with the type of virus involved. For instance, in chickens, coronaviruses tend to attack predominantly the respiratory and urogenital tracts, whilst in dogs, cats, ferrets, rabbits, turkeys, pigs and cows it affects predominantly the intestines and digestive systems leading to diarrhoea.

Humans can also be infected by coronaviruses. So far there are seven types of coronaviruses known to infect humans, four of which are responsible for mild respiratory infections and three that lead to serious and sometimes lethal respiratory infections, such as pneumonia. These include the Severe Acute Respiratory Syndrome (SARS), a disease initially discovered in China in 2003; the Middle East Respiratory Syndrome (MERS), first found in Saudi Arabia in 2012; and the most recent outbreak that started in China in 2019-2020 (Covid-19), all of which believed to have been transmitted from animals to humans.

All the three coronaviruses responsible for serious infections (SARS, MERS and Covid-19) appear to be originated in bats, that is believed to be the natural reservoir. Bats are often reservoir organisms due to their tolerant immune systems, what allows the viruses to live and reproduce in their bodies without causing any disease. But to be able to reach and infect humans, these viruses generally need an intermediate host animal. In the case of SARS, it is believed that the disease has jumped to humans through the consumption of civet cats previously infected by bats, whilst in the MERS, it is though that the transmission has occurred through dromedary camel’s meat. Scientists are still trying to understand the intermediary specie for the Covid-19 virus but it appears to have happened in a wildlife market probably during consumption of animal products. To try to identify the intermediate animal, researchers have compared the genomic sequence of the human coronavirus responsible for Covid-19 and other coronaviruses that infect several animals and they have discovered large similarities with the virus that infect pangolins, indicating that this is the most likely intermediate host.

But, can animals also get sick from Covid-19?

A lot of research is still necessary to better understand this virus, but the good news is that it looks like animals are not playing a significant role in the spread of the human disease and the risks of animals spreading Covid-19 to humans is low. To date, only a few but very exceptional cases have been reported of humans contaminating animals and one case in which animals have transmitted the virus back to humans. The Netherlands government reported in April 2020 that several minks suffering from respiratory symptoms tested positive for Covid-19 in four different farms possibly infected by humans. More recently, it was announced that two farm workers have now been infected from one of those animals, in what appears to be the first European case of transmission from animals to human. Similarly, several tigers and lions in the New York Zoo also tested positive for the disease after showing symptoms of a cough and loss of appetite. Scientists believe these animals may have been infected by a member of staff carrying the virus, however investigations are still ongoing. Similarly, there have been a small number of cases of confirmed Covid-19 reported in dogs and cats suffering from diarrhoea, vomiting and shortness of breath after being in close contact with people infected by the virus.

Several studies are underway in laboratories to understand which species can or cannot be infected by the disease. Preliminary data in a small number of animals have shown that cats, ferrets and hamsters can be easily infected by the virus and transmit it to other animals of the same species, but that dogs appear to be less sensitive to infection, whilst pigs, chickens and ducks failed to become infected.

As we learn more about this disease and the way it can affect animals, governments around the world are recommending to treat pets in the same way as we would treat other members of our household, to wash the hands frequently before and after handling animals and their food, and to contact the vet if have any questions.

How can animals help scientists fighting and understanding the disease?

Many efforts are ongoing to develop new methods of diagnosis and to discover new treatments and vaccines. To achieve that, scientists are taking advantage of animals to help them answer some of these questions.

It is already known that some dogs can efficiently detect the odour of many human diseases such as cancer, Parkinson’s diseases, diabetes and malaria. Scientists in the UK (at the London School of Hygiene and Tropical Medicine and Durham University) and around the world are now trying to find out if trained sniffer dogs can also be able to reliably detect Covid-19 infections in people even before symptoms appear. So far, preliminary studies seem promising and if successful, this could unleash a new non-invasive tool and a potent early warning measure to detect coronavirus and to help control the spread of the disease.

Some other studies and trials are underway to learn if llamas can help protect humans against this virus. Humans produce antibodies, proteins that recognise the virus and attach to their surface to help in destroying it, but scientists have found that camels, llamas and alpacas produce a small version of these antibodies, called nanobodies. Due of their smaller size, nanobodies are more stable and capable of attaching and sneak into certain pockets of the virus surface, that otherwise human antibodies would struggle. Studies in Belgium have previously shown that nanobodies derived from llamas are efficient in fighting SARS and MERS and scientists are now working towards clinical trials to understand if this is also possible against Covid-19.

Apart from dogs and llamas, scientists also take advantage of other species to help study the disease and to develop vaccines and new treatments. Mice are often used to test the safety of vaccines and therapies before testing in humans. Due to its close proximity with humans, non-human primates such as monkeys are used to help understand how the virus work inside the body, as well as to test the safety and the efficacy of new treatments or if people can be repeatedly infected by the virus. Finally, researchers are taking advantage of other species, such as ferrets, hamsters and cats, because they are good models of the disease or because they can be easily genetically modified to become susceptible to Covid-19 infection.

But, why are animal-derived diseases getting more frequent nowadays?

In the last century, we have witnessed a rapid emergence of new infectious diseases transmitted from animals to humans (zoonosis), such as Ebola, HIV, Swine-Flu, Bird-Flu and several coronavirus infections like SARS, MERS and now Covid-19. But why are these outbreaks becoming more frequent? The fast-growing world population and the development of large metropolis are pushing animals away from their natural habitat, allowing humans to intermingle with wildlife and encouraging the trade of isolated groups of animals often carrying microorganisms to which humans have never been in contact with. Additionally, environmental and climatic changes are causing alterations in temperature and rainfalls therefore shifting animal habitats and ecosystems, altering life-styles, geographic locations and eating habits (who eat whom). The increasing consumption of animal meat is another important factor contributing to the rise of zoonosis as a result of the increased consumption of wild animals, the intensification of greenhouse gas emissions and the deforestation of massive areas for farming and the animal food industry. Finally, and to worsen the situation, the escalation of international travel further contributes to the rapid spread of these diseases.

History has repeated itself and humans are once again suffering the consequences of altering Earth’s habitats and environments. Hopefully lessons will be learned from this pandemic, helping reshape human’s future decisions.

By Ricardo Ribas, Veterinary Doctor, doctorate in veterinary sciences and researcher in the area of oncology in London

References

1. Xiao K., Zhai, J et al. Isolation of SARS-CoV-2-related coronavirus from Malayan pangolins, Nature, 2020, DOI- 10.1038/s41586-020-2313-x

2. Shi, J; Wen, Z et al. Susceptibility of ferrets, cats, dogs, and other domesticated animals to SARS–coronavirus 2. Science, 2020, DOI: 10.1126/science.abb7015

3. Wrapp, D; Vlieger, DD. Structural Basis for Potent Neutralization of Betacoronaviruses by Single-Domain Camelid Antibodies. Cell, 2020, DOI: 10.1016/j.cell.2020.04.031.

4. Questions and Answers on the COVID-19. World Organisation for Animal Health, 2020, https://www.oie.int/en/scientific-expertise/specific-information-and-recommendations/questions-and-answers-on-2019novel-coronavirus/. Accessed June 2020

5. Coronavirus. World Health Organisation, 2020, https://www.who.int/health-topics/coronavirus, Accessed June 2020

6. Coronavirus Disease 2019 (COVID-19). Pets and other animals. Centre for Disease Control and Prevention, 2020, https://www.cdc.gov/coronavirus/2019-ncov/animals/pets-other-animals.html. Accessed June 2030

7. Coronavirus (COVID-19): advice for people in England with animals. Department for Environment, Food & Rural Affairs and Animal and Plant Health, Gov.uk, 2020, https://www.gov.uk/guidance/coronavirus-covid-19-advice-for-people-with-animals. Last update 18 May 2020. Accessed June 2020

8. COVID-19 detection dogs trials launches. Department of Health and Social Care, Gov.uk, https://www.gov.uk/government/news/covid-19-detection-dogs-trial-launches. Published 16 May 2020. Accessed June 2020

9. Coronavirus, Wikipedia, Wikipedia Foundation, last updated 06.06.2020, https://en.m.wikipedia.org/wiki/Coronavirus

10. Coronavirus disease 2019, Wikipedia, Wikipedia Foundation, last updated 06.06.2020, https://en.m.wikipedia.org/wiki/Coronavirus_disease_2019

11. Bronx Zoo Tigers and Lions recovering from Covid-19, WCS news Release, 21 April 2020, https://newsroom.wcs.org/News-Releases/articleType/ArticleView/articleId/14084/Update-Bronx-Zoo-Tigers-and-Lions-Recovering-from-COVID-19.aspx

12. Toby Sterling, Mink infected two humans with coronavirus: Dutch gov’t, world news, 25 May 2020, https://www.google.co.uk/amp/s/uk.mobile.reuters.com/article/amp/idUKKBN2311QA

13. COVID-19 / SARS-CoV-2, AnimalResearch.info, 2020. http://www.animalresearch.info/en/medical-advances/diseases-research/sars-cov-2/, Last edited: 30 April 2020, Accessed June 2020

Disclaimer

The material and ideas discussed in this article are for informational purposes only. For more information consult a vet or a professional in the area. Whilst every effort is made to make sure the article is accurate at the time of publication, I take no liability for any new developments on the subject as well as any errors or omissions.

Ticks: the vampire of the parasites

Spring has sprung and unlocked the tick’s season. Learn more about this blood eater parasite and which diseases it can bring to you, your family and animals.

By Ricardo Ribas

UNDERSTANDING THE TICKS?

Ticks are small external parasites that together with the spiders, mites, harvestmen and scorpions form the group of the arachnids. Arachnids are a type of invertebrated animals with their bodies divided into two main compartments: the cephalothorax, corresponding to the front part of the body (containing the head and thorax) and the abdomen. Adults ticks are usually 3-5mm long, ovoid or pear-shaped with eight legs that often become engorged as they feed on blood. Blood is essential for the ticks life-cycle and survival, hence their dependence on vertebrate animals, such as mammals, birds, reptiles, amphibians, as well as humans. But, as blood-eaters, ticks can cause considerable harm to their host either directly or indirectly by transmitting infectious agents. There are more than 800 species of ticks worldwide subdivided into two major groups, according to the presence or absence of a dorsal hard shield: the Ixodidae or hard ticks and the Argasidae also called soft ticks. Hard ticks are the most abundant in nature, accounting for more than 650 of the known species, whilst the soft ticks account for about 155 species. Fossil records suggest that ticks are very old parasites, having been around for over 90 million years.

WHERE DO THE TICKS LIVE?

Ticks are widely distributed around the world, but prefer humid and warm conditions. Spring is their favourite season coinciding with the time when people and animals spend longer periods outside. To help them locate blood, ticks possess senses that attract them to the host smells and body temperatures. Additionally, they often position themselves strategically, such as in tall grasses, which provides them in an ideal spot to crawl and ride into passing hosts. Once attached to the host, ticks can appear anywhere in the body but they often opt for warm and moist areas, such as the armpits, groin and scalp in humans and the head, ears, anus and between the digits in animals.

MORE ABOUT THEIR LIFE CYCLE…

Ticks life-cycle is divided into four main stages: eggs, larva, nymph and adult. Both males and females attack together, but it is easy to distinguish because the females tend to increase their volume, as they feed in blood. Each adult female can produce between 2,000 and 20,000 eggs at one time, often laying them in areas of moist vegetation, where they have higher chances of meeting the hosts. Depending on the species, ticks may require one, two or three hosts.

HOW HARMFUL ARE THEY?

Ticks can seriously harm and even kill their hosts, raising concerns for public health. As blood-eaters, they are often responsible for anaemias, skin inflammations and allergies, conditions particularly serious in livestock and accountable for serious repercussions in the wool and animal-source food industries. Some types of ticks can also produce neurotoxins that can cause paralysis or even lead to death of their host. Luckily, toxicity can be reversed by removing the tick. However this should be done carefully to avoid leaving traces of the tick’s mouth in the host’s skin.

Recent studies have also shown that some ticks are responsible for a type of food allergy to red meat, called Alpha-gal syndrome. When feeding on animal’s blood, particularly cattle and sheep, ticks ingest a sugar molecule called alpha-gal. This sugar is stored in the tick’s saliva and subsequently injected in the human’s bloodstream as they feed. In some people, this triggers a strong immune response that culminates with the development of allergies after consumption of red meat often accompanied by hives, itchy skin, swelling of the lips, tongue, throat and face, abdominal pain, diarrhoea and vomiting, wheezing and shortness of breath. Interestingly, alpha-gal syndrome sufferers do not require to become fully vegetarians, as fish and poultry meat consumption does not trigger the reaction. Unlike most food allergies, alpha-gal allergy can disappear over time.

However, ticks are also be involved in the transmission of infection diseases caused by bacteria, viruses and parasites. Tick-Borne Relapsing Fever and Lyme diseases are examples of bacterial infections transmitted by ticks. Tick-Borne Relapsing Fever is predominantly found in North America, Africa, Asia, Middle East and Spain causing fever and flu-like symptoms in humans, dogs, horses, cattle, deer, mice, chipmunks and racoons. Lyme disease is present mainly in North America and Euroasia. The majority of the animals infected by this disease rarely show symptoms, but dogs often develop fever, lameness and joint pain (arthritis), that in rare cases can develop to heart and kidneys complications and death. Human experience flu-like symptoms accompanied by a red bump in site of the bite that can spread into a larger circular red rash. In some cases, the disease can progress and spread to other organs causing joint pain as well as heart and brain complications. Antibiotics are effective, particularly if administered in the earlier stages.

Other examples of bacterial infections carried by ticks are Ehrlichiosis, Anaplasmosis and Rocky Mountain Spotted Fever, all caused by a Rickettsial-like bacteria, an obligate intracellular microorganism transmitted by arthropods. Ehrlichiosis and Anaplasmosis are globally distributed and responsible for attacking and destroying the host’s white and red blood cells, respectively. Rocky Mountain Spotted Fever is mainly present in the USA and once inside the host it attacks the blood vessel cells. All conditions affect humans and dogs causing fever, flu-like symptoms, diarrhoea, weight loss, anaemia and bleeding disorders such as presence of blood in the urine as well as the presence of erythema and small red rashes in the skin and the conjunctiva caused by broken blood vessels. Antibiotics are efficient, but if delayed, can lead to brain damage, respiratory failure and, in the case of the Rocky Mountain Spotted Fever, to hearing complications and the loss of parts of the limbs. All conditions could lead to death if not treated.

Finally, Tularemia or Rabbit fever is another example of a rare and highly contagious bacterial disease, particularly found in North America and Euroasia and characterised by the appearance of skin ulcers in humans, dogs, cats, rabbits and rodents. Antibiotics are efficient to prevent complications and death.

Nevertheless, ticks are not only vectors of bacteria. They can also transmit parasites such as the case of the Babesia, a single cell organism belonging to the group of protozoa. Babesiosis or Cattle Tick-Fever is a global distributed disease, affecting both humans as well as wild and domestic animals. Once inside the host, the protozoa attack and destroys the red blood cells and leading to flu-like symptoms, dark-colour urine and jaundice, a yellowing of the skin and mucous membranes due to a bile disorder. In severe cases, the parasite can travel to other parts of the body such as the kidneys, lungs and brain and cause incoordination and potential death. Despite the fact that a wide range of animals can be affected, babesiosis is particularly concerning in cattle and buffalo due to the economic impact imposed in cattle industry. Unfortunately, the disease appears also to blame for many wild life causalities over the years, such as the outbreak in Tanzania in early 2000s that killed many rhinos, lions, buffalos, wildebeest and zebras. Fortunately, antibiotics, quinine and vaccination are effective to treat and prevent the disease.

Finally, ticks can also transmit viruses such as the ones responsible for the Powassan disease in North America and the Tick-borne encephalitis in Euroasia, both affecting the brain and causing a variety of neurological symptoms in humans including mental confusion, loss of memory, seizures, difficulties in speech and lack of coordination. Tick-borne encephalitis can also affects carnivores, ruminants, horses, birds and rodents. Other examples of viral diseases include Colorado Tick Fever in the western parts of North America and the Crimean-Congo Haemorrhagic Fever, a disease endemic in Africa, Middle East and Asia. Whilst often asymptomatic in animals, CCHF can cause serious problems in humans leading to bleeding of the skin and mucosa and responsible for death in 40% of the cases, constituting a public health threat. Unfortunately, antibiotics are not efficient in the treatment of these virus diseases, so prevention is the preferable strategy.

PREVENTION: TOP PRIORITY

The best way to avoid and control tick’s infestations is to implement prevention measures. Here are some tips:

• Use insect repellents both in humans and animals. A wide variety of sprays, powders, topical products, shampoos and collars for animals are available in the market.

• Try to cover up with clothes when going to grassy and bushy areas

• Whenever find a tick, remove it with gloves or tweezers by grasping it near the mouth to avoid leaving traces of the tick’s mouth on the host’s skin. After removal, burn the tick, disinfect the area and wash your hands in soap and water.

• If notice ticks in your garden, apply mite sprays.

• Inspect frequently for the presence of ticks on yourself, children and on the animals, especially in areas where ticks regularly appear.

• Vaccinate humans and animals against some of the tick-borne diseases, such as Lyme disease and babesiosis, which have an efficiency of 70 to 100 percent.

• People affected by alpha-gal syndrome should refrain from eating red meat.

By Ricardo Ribas, Veterinary Doctor, doctorate in veterinary sciences and researcher in the area of oncology in London

Reference Sources

1. Simon LV, West B, McKinney WP. Tick Paralysis. [Updated 2020 Apr 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan. 2020 Apr 28. PMID: 29262244

2 Mabelane T, Ogunbanjo GA. Ingestion of mammalian meat and alpha-gal allergy: Clinical relevance in primary care. Afr J Prm Health Care Fam Med. 2019;11(1), a1901. https://doi.org/10.4102/phcfm.v11i1.1901

3. Elelu, N. Tick-borne Relapsing Fever as a Potential Veterinary Medical Problem. Vet Med Sci. 2018 Nov;4(4):271-279. doi: 10.1002/vms3.108.

4. Chomel, B. Lyme Disease. Rev Sci Tech 2015 Aug;34(2):569-76.doi: 10.20506/rst.34.2.2380.

5. Ismail, N; Bloch, KC; McBride, JW. Human Ehrlichiosis and Anaplasmosis. Clin Lab Med. 2010 Mar;30(1):261-92. doi: 10.1016/j.cll.2009.10.004.

6. Nijhof, AM; Penzhorn, BL et al. Babesia bicornis sp. nov. and Theileria bicornis sp. nov.: Tick-Borne Parasites Associated with Mortality in the Black Rhinoceros (Diceros bicornis). J Clin Microbiol. 2003 May; 41(5): 2249–2254. doi: 10.1128/JCM.41.5.2249-2254.2003

7. Shi, J; Hu, Z et al. Tick-Borne Viruses. Virol Sin 2018 Feb;33(1):21-43. doi: 10.1007/s12250-018-0019-0.

8. Tick, Wikipedia, Wikipedia Foundation, Last update: 30 April 2020. https://en.m.wikipedia.org/wiki/Tick, Accessed May 2020

9. Tick-borne disease, Wikipedia, Wikipedia Foundation, Last update: 25 April 2020. https://en.m.wikipedia.org/wiki/Tick-borne_disease. Accessed May 2020

10. Tularemia. Wikipedia, Wikipedia Foundation, https://en.m.wikipedia.org/wiki/Tularemia. Accessed May 2020

11. Ticks, Centers for disease Control and Prevention, last reviewed 28 May 2020, https://www.cdc.gov/ticks/index.html, Accessed May 2020

12. Carter, PD & Rolls, P. Babesiosis. MSD Manual, Veterinary Manual. Last update: Feb 2015. https://www.msdvetmanual.com/circulatory-system/blood-parasites/babesiosis. Accessed: May 2020

Disclaimer