Emergence of Tick-Borne Zoonotic Parasites in Livestock and Companion Animals in Pakistan

Ullah K, Sabir M, Fareed J, Shafqat J and Zubair Z

Published on: 2024-07-18

Abstract

Ectoparasites like lice, ticks and mites depend on host organisms for survival and maturation. Among these Ticks are prevalent because of favourable climate conditions. Ticks are obligate blood feeding parasites that infest both livestock and companion animals transmitting pathogens across animals and humans. Tick fauna comprises at least 40 species mainly belonging to Haemaphysalis, Hyalomma,Rhiphicephalus, Ixodes, Ornithodoros, Otobius, Amblyomma and Dermacentor.Anaplasma, Babesia and Theileria species are the major tick borne pathogens causing disease like Crimean – Congo haemorrhagic Fever,Theileriosis, Babesiosis and Anaplasmosis. Prevalence of ticks is highest in summer (June to September). Although ticks are crucial factor related to livestocks animals, there has not been enough Research done on ticks. Morphological examination along with techniques like PCR, PCR- RLB, Microscopy and ELISA have been used for identification of ticks. Pakistan is an agricultural country with significant presents of livestock which are crucial for livelihood of farmers. Ticks and Tick Borne Disease (TTBD) affect production of livestocks significantly on livelihood of farming communities. Livestock sector is an important part of Pakistan’s economy and a large number of cattles and sheep are being imported to meet increasing demands of milk products. Research must be done on ticks to gain further knowledge and precautionary measures must be taken. Just like Livestock animals, Companion animals like cats and dogs can also get infested with ticks, thus teaching their owners about the disease and parasites these companion animals bring with them are of paramount importance. Our Article is based on descriptive data rather than statistical data and aims to spread awareness about ticks and tbds.

Keywords

Babesiosis, Anaplasmosis, Economic effect, Pakistan, Livestock and Companion animals

Introduction

About 80% of Global Livestock population is affected by Ticks [1]. Accelerating Global warming and humidity are contributing to increase in number of parasites and infectious diseases [2]. Ticks often harbour multiple pathogens forming complex communities known as “pathobiomes” [3]. Ticks play role in transmitting infections from animals to Humans [1] Livestock animals like cows, goats, sheeps provide not only meat but also provide milk, wools and skin and are of economic value, However environmental conditions or parasitic diseases (TTBDs) pose significant health problems [4]. Sub-tropical climate of Pakistan favors tick infestation. Major tick-borne diseases include theileriosis [5].Ticks infested livestock have deceased milk production and increased mortality rate [1]. Just like livestock animals, companion animals like dogs and cats also contribute significantly to health and well-being of their owners.

Awareness and prevention of diseases like Leishmaniasis, Chagas’s disease, Giardia duodenalis are crucial, although some of these diseases are regional with low prevalence rate, they pose significant health risk to immunocompromised individuals [6].

Our article aims to raise awareness about ectoparasites like ticks, their pathogenicityImportance of livestock and companion animals:food security means when everyone has access to healthy food forhealthy lifestyle at all times [7]. Livestock farming is important for our economy [8]. Milk, meat etc are important part of food security due to being an important source of proteins, micronutrients like iron, zinc, and many more nutrients. Farm animals/livestock animals along with being a source of food also provide additional resources such as manure for fertilizers and provide skin that is used to make leather boots, jackets, and shoes, etc, additionally providing economic diversification and risk distribution of infectious diseases and pathogens [9]. Livestock farming is also crucial for farmers since their livelihood depends on them.

Although companion animals cannot provide meat and other benefits, they do have therapeutic effects in relation to mental health and provide benefits to people with mental health conditions [10]. However, regardless of being mental support, these tiny adorable pets can also carry parasites and pathogens of infectious diseases.

Ticks, Brief Introduction

Ticks are the small creatures (arthropus) related to the Spiders and Belong to class Arachnida. There are two main types of ticks;hard ticks (Ixodidas) and Soft ticks (Argasidae).Both types are important in human and animal health because they can spread diseases, harm their hosts, and sometimes even cause death. Ticks cause huge financial losses in the livestock industry worldwide because of the diseases they spread to animals. There are over 900 different species of ticks [11] the number of species of hard ticks (Ixodidas) are greater than that of soft ticks (Argasidae) [12] and are composed of 18 genera.

Mode of Transmission

Ticks becomes a vector if it feeds on an infected host, acquires the pathogen, maintains it through life cycle and transmits it to other hosts .Disease transmission to Animals are transmitted when an infected tick feeds on an animal, The pathogen must multiply within the tick before it can infect new Host through tick saliva & mouthparts. Ticks can become infected by

Feeding on an infected Host.
Trans-stadial transmissions: passing the pathogen through life stages (larva, nymph, adult).
Trans-ovarial transmission, passing the pathogen from parent Ticks to offspring via ovaries.

Ticks can stay infected for long periods up to 15 months. Pathogens are transmitted through tick saliva, regurgitation of feces when feeding. Longer tick attachment increases the risk of disease transmission. Diseases spread among animals through movement of tick vectors and reservoir hosts.

For TTBDS to spread to new areas, ticks or Hosts must find susceptible Animals [13].

Pathogenicity of Ticks

Hard-bodied and soft-bodied female ticks are believed to make toxins that can cause paralysis. Tick paralysis is caused when toxin from tick salivary glands enters into patient during blood meal. The toxin causes symptoms within 2-7 days, starting from legs to trunks, arms and then eventually causing death [14] approximately 43 tick species across 10 genera are known to cause tick paralysis [15]. Tick paralysis occurs when female tick bearing eggs produces neurotoxin in its salivary gland & transmits it during feeding.

Experiments have shown that greatest amount of toxin is produced between 5th & 7th day of tick attachment. babesiosis are caused by multiplication of microbes that remain after the tick is removed or killed, tick paralysis is induced by tick and therefore usually only continues in its presence. Once the tick is removed, symptoms usually disappear [14]. Studies have shown that the area/lesion affected by tick neurotoxins is probably near the neuromuscular junction [16].

Life Cycle

Similar to spiders, ticks are classified as arachnids and not insects due to the same characteristics of having eight legs and no antennae. The tick life cycle is composed of four stages: eggs stage (initial stage), stage 2: nymph, and adult/ mature stage with duration varying based on species.

Stage 1: Larvae

The first stage is larva, which after hatching attaches to tiny vegetation like grass, leaves, etc and waits for hosts like rodents, lizards, mice to approach, feeding on their blood to molt into a nymph. It senses the host through lactic acid, carbon dioxide, ammonia, and body heat.

Stage 2: Nymph

The second stage is nymph, where it has eight legs and is larger, usually not feeding in winter. When ready, it seeks larger hosts like raccoon, fox or cats, molting into adult form.

Stage 3: Adult Form

The third and most mature stage is adult form, which feeds on larger hosts like humans, cows, dogs, etc and mates. Male ticks die post-mating and females die after laying eggs.

Stage 4: Eggs

Females lay between 1000 and 18000 eggs on the host or ground. Eggs hatch in summer, starting the cycle anew.

Difference between hard and soft ticks in their life cycle is that soft ticks don’t die after mating and lay several egg batches. Female hard ticks are larger and differently colored than males, while male and female soft ticks look more similar.

Diseases Caused By Ticks

During feeding, ticks can get infected with bacteria, viruses, and Pathogens and can transmit these diseases to other animals and humans. Some of the most common diseases are: In livestock and animals, ticks can also cause paralysis, dermatitis & secondary infections [17,18].

Lyme Disease

Borrelia burgdorferi causes lyme diseases and is transmitted to humans from infected tick bites, causing fever, chills, headache, fatigue as circular, expanding rashes near the biting site [19].

Babesiosis

Babesia parasites cause babesiosis which infect red blood cells. These parasites are referred to as piroplasm due to their pear shape. The disease affects many vertebrates, with ixodid (soft) ticks acting as vectors. Symptoms can range from mild to severe and can sometimes be asymptomatic. Typical symptoms include fever, chills, fatigue, headache, nausea, loss of appetite, dark urine. In severe cases, especially in people with weak immune systems, it can cause severe anemia due to the destruction of RBCs, jaundice, heart problems, or kidney failure. The same symptoms are found in infected animals [20].

Anaplasmosis

Anaplasmosis, caused by phagocytophilum which is pathogen that is transmitted through ticks. Symptoms in humans involve headache, chills, malaise, diarrhea, confusion, rash, respiratory symptoms, and swelling. In animals, symptoms of Anaplasmosis include weight loss, lethargy, anemia, and swelling [21].

Theileriosis

Theileriosis is a tick-borne disease of domestic and wild mammals caused by parasite named haemoprotozoan [22], causing severe morbidity and deaths in livestock reducing meat and milk production, affecting economy [23]. Theileriosis infection in humans is very rare but can cause swollen lymph nodes, hepatosplenomegaly, fatigue alongside fever and sweating. In animals, it mostly affects cows leading to swollen lymph nodes, weakness, weight loss, nasal and ocular discharge, decreased milk production, and death if left untreated.

Difference between Companion Animal Ticks & Livestock

In terms of species, there isn’t much of a distinction between ticks from companion animals and cattle. Both kinds of animals are susceptible to tick infestations. The focus of control tactics and their influence on animals are where the main differences lie. Farmers may suffer large financial losses as a result of livestock ticks because of decreased productivity, anaemia, and in extreme situations, even death. Preventing tick-borne diseases-which can be dangerous but typically have no direct effect on an animal’s productivity-is more of a priority for companion animals [24]. Research indicates that adult ticks often damage companion animals and cattle the most [25].

Prevention of Tick Borne Diseases

There are three basic methods for preventing illness following a tick bite. To begin, vaccinations, such as those used to treat tick- borne encephalitis, can reduce clinical illness. However, the Lyme borreliosis vaccine was removed from North America due to issues such as frequent boosters and high cost. Second, regular tick inspections and early removal can help avoid infection spread. Lyme disease transmission often occurs after 24 hours of connection. Third, as with Lyme borreliosis, providing antibiotics promptly can lower the impact of symptoms. And may also be effective against other bacterial diseases.

To prevent tick bites when in tick habitats, simple measures can be taken like

Clothing

Wearing socks, long trousers, and long-sleeved shirts. This increases the likelihood of brushing off ticks before they reach skin.

Repellents

Applying repellents like DEET or permethrin to clothing or skin can effectively reduce tick bites. However, some people avoid these due to concerns about toxicity, leading to increased interest in natural repellents like lemon- scented oil, cedar oil etc.

Anti-Tick Vaccines

An antitick vaccine for cattle exists, but developing a human version is more complex. It must prevent both tick feeding and pathogen transmission. Vaccines targeting tick midgut antigens show promise for pathogens with a delay between tick attachment and pathogen transmission.

Alternative Tick Control Methods Include

Vegetation Management

This includes bush removal, mowing, and controlled burns, which expose ticks to desiccation. However, these effects are often short-lived.

Host-Targeted Approaches

Devices like the 4-poster device, which treats deer with acaricides, have shown success in reducing tick populations. Acaricides are chemicals applied to grasses and herbs etc to kill ticks In United States, efforts to control ticks using acaricides have shifted to less-toxic options like synthetic pyrethroids. These have proven effective, with a single application of deltamethrin killing up to 95% of host-seeking nymphs at residential forest-lawn interfaces.

Biological Control Agents

Using natural predators, parasitoid wasps, nematodes, and fungal agents (like Metarhizium anisopliae) to control ticks is being explored.

Rodent Targeting

Bait boxes and treated cotton balls targeting rodents have shown mixed results in different locations, with varying effectiveness depending on local host diversity.

Some other methods to combat tick-borne diseases include targeting pathogens within vertebrate hosts. For instance, in a Connecticut study, white-footed mice were vaccinated against B. burgdorferi, resulting in a decrease in infection rates in ticks.

Oral vaccines for mice show promise, and field trials are needed. Another approach is using doxycycline in oral baits to target multiple pathogens, but its environmental impact and the risk of antibiotic resistance require careful evaluation before widespread use [26].

Tick Borne Diseases in Pakistan

Tick-borne illnesses influencing homegrown creatures and people have expanded all around the world lately. Pakistan, specifically, faces a critical monetary danger from ticks, where two explicit species, Rhipicephalus microplus and Hyalomma anatolicum, go about as vectors for different microorganisms, for example, piroplasma, Anaplasma, Ehrlichia, and Rickettsia that represent a huge weight on animals creation in the country [27].

The spatial dispersion of TBDs is a developing general wellbeing worry because of environmental change around the world [28]. Domesticated animals assumes a crucial part in the economy of Pakistan, especially in rustic regions [29]. Coinfections from TBDs represent a danger to human and creature wellbeing around the world, especially in Pakistan. Coinfections with different TBPs can impact infection seriousness, modify illness signs and side effects, and entangle finding and treatment [30].

Diagnosis of Tick Borne Diseases

Patients who present with flu-like symptoms in the spring and summer should be suspected of tick-borne diseases because their incidence is rising. Complications and death can be avoided with prompt diagnosis and treatment. The location of the exposure, the specific tick vector, and the evaluation of the rash, if any, assist in determining the specific disease.

For instance, 70% to 80% of patients with Lyme disease have an erythema migrans rash, which means that treatment can be started right away. Rocky Mountain spotted fever (RMSF) symptoms include a petechial, macular rash that begins on the wrists, forearms, and ankles. RMSF has a higher pace of mortality than other tickborne illnesses; hence, empiric treatment (treatment in view of surmise) with doxycycline is suggested for all patients, including pregnant ladies and youngsters.

Ticks can transmit multiple diseases in the same area, and the majority of patients do not remember being bitten by a tick. Additionally, the initial symptoms of tick-borne diseases are similar and nonspecific. Early in the course of the disease, the sensitivity of the available diagnostic tests is low, making clinical familiarity and suspicion much more challenging. [PCR, Elisa, and morphological examinations are utilized in laboratory settings for the purpose of diagnosing tick-borne diseases [31].

Ecological/Economic Effects of Ticks and Tbds

It is inevitable that livestock will play a role in enhancing a nation's economy. In developing nations, livestock accounts for the majority of the agricultural sector's contributions. In order to boost native breed productivity and reduce disease resistance, a number of developing nations have adopted the use of germplasm. Parasitic issues play a significant role among the many obstacles to livestock growth and productivity. Eighty percent of all cattle in the world carry tick-borne and other diseases. They transmit major pathogens that cause disease and jeopardize the health of animals, resulting in poor production, both of which present a number of challenges for farmers. Ticks also carry a variety of pathogens, including viruses, bacteria, protozoa, and other parasites. Many of them pose a threat to livestock health and are also zoonotic, so early detection is necessary. Control of ticks is the main pressing issue in the current circumstance as the utilization of hostile to parasitic medications has prompted the latest thing of opposition improvement [32].

Livestock animals contribute not only milk and meat products but also provide leather and fertilizer. Livelihood of farmers in rural areas depend on them, these diseases affect milk and meat production, adversely affecting economy. Ecologically due to climate changes and global warming, ticks infestation are increasing drastically.

Conclusion / Suggestions

Tick borne diseases and ticks are threat to livestock animals and farmer’s livelihood and can sometimes cause paralysis. The rise of tick-borne diseases in our livestock and pets is becoming a serious issue, one that we can’t afford to ignore. With changing environments and more frequent animal movements, ticks are finding new places to live and thrive, spreading diseases to animals and, indirectly, to humans.

To solve this problem effectively. First, we must improve our ability to spot and track these parasites early through better surveillance systems. Alongside this, developing more effective diagnostic tools and treatments will help us manage and reduce the impact on our animals. Educating people about how to prevent tick bites and control tick populations is also crucial.

Journal of Marine Biology and Environmental Sciences