Methylene Blue : A Promising Antiviral Drug for Treatment of Lumpy Skin Disease ( LSD) in Cattle
What is Lumpy Skin disease?
Lumpy skin disease, or LSD, is an infectious disease that affects cattle and is caused by a virus belonging to the family Poxviridae, also known as Neethling virus. It originated in Africa and has since migrated to the Middle East, Asia, and eastern Europe. It is transmitted by insects that feed on blood such as mosquitoes, ticks, and certain species of flies. It can also spread through contaminated fodder and water.
The risk is greatest during the wetter months of summer, but it can also occur in the winter. The incidence and severity of the disease vary quite a bit amongst different cow breeds and strains. It causes fever and multiple nodules on the skin. In addition, chronic debility (physical weakness), decreased milk production, poor growth, infertility, miscarriage, and even death especially in animals that have not previously been exposed to the virus. The virus also has important economic implications since affected animals tend to have permanent damage to their skin, lowering the commercial value of their hide.
Some of the common symptoms of Lumpy Skin disease-
Infected cattles develop the following symptoms-
- Fever- The onset of fever starts around one week following viral infection.
- Lacrimation (excessive flow of tears)
- Nasal Discharge
- Hypersalivation
- Cutaneous lesions or multiple nodules – well-defined growths that are typically spherical, somewhat elevated, firm, and extremely painful measuring 2–5 centimetres (1–2 in) in diameter) on the skin and mucous membranes (including those of the respiratory and gastrointestinal tracts).
- Additionally, infected cattle could develop edematous swelling in their limbs and show signs of lameness (an abnormal stance or gait).
- Systemic effects include pyrexia (fever), anorexia, dysgalactia and pneumonia.
Treatment for Lumpy Skin disease-
- Antiviral treatment with Methylene Blue
- Use of Non-steroidal anti-inflammatory drug to treat the inflammatory condition
- Use of Paracetamol for high fever
- Administration of antibiotics to control secondary infection
- Vaccination
How does Methylene Blue help in Lumpy?
Methylene Blue (MB) is a broad-spectrum antiviral agent and its anti-viral properties are well-known against a wide variety of viruses. Methylene Blue was recently also proven highly-effective in reducing the viral load of SARS-COV2.
MB will help in the treatment of Lumpy Skin disease by reducing the viral load in the infected cattle, through its multi-mechanism antiviral action till the body triggers natural immune-response and thus helps in preventing any damaging excessive immune-response, protecting from further complications like multiple organ damage.
It helps in faster recovery (reduces recovery time span) and decreases the mortality rate.
Mechanism of action of Methylene Blue as an antiviral agent
Methylene Blue has broad-spectrum virucidal action in the presence and absence of light and has been demonstrated to be effective at inactivating a variety of viruses. The antiviral activity appears to rely on various pathways and is more effective against enveloped viruses (as in case for viruses belonging to the family of Poxviridae).
MB is known to corrupt DNA or RNA integrity due to a redox reaction in which the molecule accepts electrons on its aromatic thiazine ring, thus being reduced to leuko-methylene blue (MBH2) which in turn transfers electrons to other molecules such as nucleic acids.
In addition, MB in combination with oxygen and a source of energy produces singlet oxygen, a highly reactive reaction partner that triggers guanine oxidation (8-oxo-7,8-dihydroguanine (8-oxoGua) lesions) that damages DNA or RNA.
Other pathways responsible for nucleic acid damage include-
- Modifying carbonyl moieties on viral proteins
- Single-strand breaks (ssb) in the RNA genome of the virus
- RNA-protein crosslinking
In addition to this nucleic acid damaging ability, it has been demonstrated that MB is capable of inactivating viruses such as HIV by targeting both the envelope (binding to the spike proteins of the viral envelope) and core proteins of the virus.
MB and its derivatives also cause marked decrease in viral binding, fusion, entry and gene expression.
Photodynamic action of Methylene Blue
Methylene blue (MB) is a hydrophilic phenothiazine derivative. It acts as an efficient photosensitizer and can be triggered by light in order to generate reactive oxygen species (ROS). These ROS have the potential to harm the cell structures of microbes as well as sick mammalian cells, ultimately leading to cell death of unwanted/infected/foreign cells. In addition to this, MB is a photosensitizer that doesn’t cost very much and is thus used as a potent Photodynamic therapy (PDT) drug because of its effectiveness against a wide variety of microorganisms, including viruses, bacteria, and fungus
It has a peak absorbance of light at 660 nm.
Photodynamic action of Methylene Blue against LSD virus-
An article with the title “The Role of Some Photosensitizers in Photodynamic control of Lumpy Skin Disease” published on https://www.researchgate.net/ in 2013, it was stated that methylene blue have efficient photodynamic activities on Lumpy Skin disease Virus (LSDv), and therefore can serve as a promising photosensitizer for controlling LSDv.
How is methylene blue treatment administered to Lumpy infected cattle?
As per the document (D.O No. K-11053/69/2019-LH) released by the Government of India, Ministry of Fisheries, Animal Husbandry & Dairying, treatment by Methylene Blue (MB) may be administered as follows :-
Oral treatment with 0.1 % Methylene Blue (MB) solution (1 gram of Methylene Blue USP powder in 1 Litre of water) may be considered by the veterinarian, with dosage as follows:
- Adult cows (of approximately 350 kg body weight): 300 ml at 8 hourly intervals (thrice in a day) for 4 days.
- Calf: give approx. half dose.
MB solution/Preparations may also be used topically (eg. by spray).
Precaution: A milk withholding interval of 96 hours and a meat withdrawal interval of 14 days (if used in meat producing animals) is advised.
Safe dosage– upto 10mg per kg body weight/day
Reference: https://megahvt.gov.in/notification/LSD_Treatment_Guidelines.pdf
CAUTION: Methylene Blue dye or lab reagent should not be considered to be same/equivalent to the “Pharmaceutical Methylene Blue USP” and should not be used as an alternative to “Methylene Blue USP” for treatment.
Why is Methylene Blue treatment considered safe?
- Methylene Blue being a very old drug having a well-established toxicology and safety profile.
- While Methylene Blue has been a part of the World Health Organisation (WHO) Model List of Essential Medicines for a long time, India also has recently included Methylene Blue in its National list of essential medicines, released as on 13 September 2022.
- Methylene blue is an FDA (food and drug administration) and EMA (european medicines agency) approved drug with an excellent safety profile.
- Due to its antimicrobial, anti-inflammatory and antitoxic effects, MB is also used for a wide range of applications including treatment of methemoglobinemiaor malaria.
WHO Model List of essential medicines –https://www.who.int/publications/i/item/WHO-MHP-HPS-EML-2021.02
National List of Essential Medicines- https://main.mohfw.gov.in/newshighlights-104
FAQs-
- How long does Lumpy skin disease take to heal?
Recovery may need a number of months and may be prolonged if additional bacterial infections develop. The purpose of treatment is to prevent or control subsequent infection. It may take up to six months for seriously infected animals to recover from the LSD virus.
- Which grade of Methylene Blue should be used for the treatment of Lumpy Skin disease in cattle?
Only pharmaceutical grades of Methylene Blue such as Methylene Blue USP, EP, BP should be used for the treatment of Lumpy skin disease in cattle. Other Laboratory, AR and dye-grade of methylene blue should not be used as they contain high content of harmful heavy-metals such as zinc (up to 30%).
- What is the cause of Lumpy skin disease?
The condition known as lumpy skin affects cattle and is caused by a virus. Insects that feed on blood, like particular types of flies and mosquitoes, as well as ticks, are responsible for its transmission.
- Is Lumpy Skin disease painful ?
The nodules which develop the skin and mucosal membranes of cattle are painful.
- Which medicine is best for Lumpy Skin disease?
Methylene Blue USP can serve as an efficacious medicine against Lumpy Skin disease virus.
Source- https://www.macsenlab.com/blog/methylene-blue-treatment-for-lumpy-skin-disease-in-cattle/#:~:text=Which%20grade%
