Study reveals excessive use of antibiotics in treating poultry

What you need to know:

  • New study warns the excessive use of antibiotics in Tanzania’s poultry industry poses a serious health risk to consumers and leads to the emergence of antibiotic-resistant bacteria in the chicken itself.

Dar es Salaam. Excessive use of antibiotics in Tanzania’s poultry industry poses a serious health risk to consumers and leads to chicken developing antibiotic-resistant bacteria, a new study warns.

The study, titled Determination of Sulphonamides and Residues in Liver Tissues of Broiler Chicken Sold in Kinondoni and Ilala Municipalities, Dar es Salaam, Tanzania, was conducted by Winstone Ulomi, Fauster Mgaya, Zuhura Kimera and Mecky Matee from the department of Microbiology and Immunology of the Muhimbili University of Health and Allied Sciences (Muhas).

Details of the study

The cross-sectional study was meant to determine the concentrations of sulphonamide and tetracycline residues in the liver tissues of broiler chicken sold in Dar es Salaam, and whether the amounts found was within the legally and acceptable limits in food.

The study indicated all the samples collected contained tetracycline remnants, although 21.4 percent showed the existence of sulphonamide remains, and those containing both sulphonamide and tetracycline residues were 21.4 percent of the collected sample.

While the study acknowledged the concentrations of sulphonamide to be within the maximum residue limit (MRL), but 90.5 percent of samples had tetracycline levels that exceeded the acceptable daily intake (ADI).

According to the study, the samples, which contained tetracycline levels that exceeded the maximum residue limit, stood at 13.1 percent.

The report established that the matter is largely fuelled by the use of antimicrobial in animal feed, which is related to intensified farming.

Animal products consumption

It is projected that Tanzania’s pork consumption will rise to 170,000 tonnes by 2030 from the current 42,700 tonnes, similar estimates have it that the annual poultry meat industry will increase by 148 percent in 2030 from the current 37,200 tonnes.

Tetracycline, sulphonamides, penicillin, aminoglycosides, and macrolides, are commonly used antibiotics in poultry production in Tanzania.

However, it is reported that tetracycline is the most consumed (8,057,240 kilos) antibiotic in animal poultry farming annually, followed by sulphonamides and trimethoprim (3,057,240 kilos).

“The said antibiotics are readily available from veterinary shops and vendors and are accessed easily without any prescription being required or restrictions imposed,” reads part of the study.

It adds: “Most farmers have inadequate knowledge and inappropriate attitudes and practices regarding the judicious use of antibiotics, posing serious human and animal health issues.”

What antibiotics are

When reached for comment, Dr Nickson Ng’umbi, a veterinary practitioner, said: “Antibiotics are medicines that may function by either killing the bacteria or by inhibiting the growth and proliferation of bacteria hence allow the animal’s immune system to more effectively fight an infection.”

According to Dr Ng’umbi, there is no way that veterinarians can dispense animal medications meant for human use. Adding: “By the way, animal medications are always marked ‘Not for Human Consumption’”.

The veterinary practitioner was of the view that the bigger risk lays on the use of wrong drug and wrong dosage. This is a serious problem farmers just diagnose infection and then try to treat it with an antibiotic meant for humans.

Dr Ng’umbi, who also runs his own combined ruminants and poultry farm, explained that animals are vulnerable to bacterial infections as people, these include pneumonia and skin infections, and that the infections can be treated with antibiotics.

He further noted that similar to humans, antibiotics are used in animals to treat, control, and prevent diseases. Moreover, a prescription is needed as there are practical considerations when one is administering antibiotics to large groups in a farm.

“I have seen the majority of farmers in WhatsApp groups where they ask for solutions, after discovering bacterial infections with their poultry, then a certain drug is proposed by a farmer who isn’t a veterinary practitioner. In fact, diagnosis may not be correct as the antibiotic proposed, but the farmer will proceed and purchase the same,” he recalled.

He added that: “Honestly, it is indeed a disaster without effective antibiotics, bacteria can’t be kept in check which will result in terrible and deadly infections. So, we need to engage a trained veterinarian as without them, then we are finished.”

He therefore called on those involved in veterinary practice to perform their duties diligently and abide by the ethics and moral principles guiding their profession.

The practitioner added: “And, veterinary drugs shouldn’t sold to a customer if they don’t present an appropriate prescription note from a practitioner.”

Lack of information

For her part, Dr Hadija Suleiman a medical practitioner from a Dar es Salaam based Agape Polyclinic explained that although antimicrobials are extensively used in Tanzania, there is no information related to quantitative use.

“In fact, weak regulatory framework in Tanzania causes the use of antimicrobial in animal production being unregulated, thus contributing to antibiotic resistance, and I do agree that lack of basic knowledge on the concept drug resistance among livestock and poultry keepers has exacerbated the problem,” she observed.

Moreover, Dr Suleiman explained that public health concern occurs when an animal or human illness is caused by bacteria that are resistant to so many antibiotics that the veterinarian or doctor cannot treat the patient with an antibiotic that will be effective.

According to her, all infections are potentially curable as long as the etiological agents are susceptible to antimicrobials yet on the other hand, there is clear evidence of adverse human health consequences due to resistant organisms resulting from non-human usage of antimicrobials.

How keepers obtain info

Ms Anita Jumanne, a poultry farmer based in Ubungo, admitted to using human related medicines to cure her chicks as they were not only easily accessed but also, they were affordable.

She noted: “I’m a member of several WhatsApp groups meant for poultry farmers, that is where I got this knowledge from. My chicks had what I came to know as fowl cholera. I just asked and a seasoned farmer recommended that I use azithromycin, which in fact brought good results.”

A single mother of two, said she started rearing chicken in her yard just for household consumption untill she developed an interest to go commercial, and since she has no knowledge, but the WhatsApp groups have helped her and that her business is doing great.

When asked if there were any problems resulting from using human drugs for treatment in her poultry farm, Ms Jumanne said: “I don’t see any problem. It seems this is the practice by many farmers, I was advised and found it useful. Maybe if we are told it is harmful, but no one has come forth to tell us so. Most keepers apply them.”

Drug generic versions

But Dr Michael Bihari, a medical practitioner indicated that many animal drugs were generic versions of human drugs but affirmed that it was unethical for a veterinary practitioner to prescribe human drugs for animals or poultry or vice versa.

“For example,” he said: “A veterinarian may prescribe prednisone for a pet with an inflammatory condition. This is the same drug humans can get with a doctor’s prescription.”

According to him, animal drugs, however, are different from those meant for humans. For example, drugs made for livestock are meant to be mixed with feed and may also contain harmful impurities.

Therefore, said he: “It is vital for the government and all practitioners to reduce the overall use of the said drugs which in fact can be achieved without significant negative effects on both human and animal health or productivity.

Consumer views

Poultry consumer Neema Mhando said: “I never knew of this, but due to their price, I usually suspect that I am buying unhealthy chickens, but I don’t have any proof, the government needs to protect us, it should register all keepers as with the last census, I guess the government knows all the farms.”

Media reports indicated that a number of effective upstream interventions to reduce resistance have been documented, which includes banning of non therapeutic uses in animal feeds, and enforcing prescription-only policies.

Other measures are restricting the use of drugs considered critically important for human health, monitoring usage at the farm level and providing advice to high-end users and establishing thresholds for resistant pathogens in food.

Reducing antimicrobial usage requires collaboration between experts, regulatory authorities, and producers, and integrated monitoring of the effects of interventions is essential which may be facilitated by establishing a coordinating body.

Guidelines by WHO, FAO

It is said that the Codex Alimentarius Commission (CAC) under the WHO and the FAO, has issued recommendations that should be implemented by all countries as a code of practice to minimise and contain antimicrobial resistance (CAC 2005).

It gives recommendations for the responsibilities of regulatory authorities, the veterinary pharmaceutical industry, veterinarians, and wholesale and retail distributors and producers to ensure that antimicrobial agents are prescription only.

Among other things, the code affirms that only drugs that are efficacious and with well-established dosages should be approved, surveillance programmes for monitoring drug use and resistance should be established, research should be encouraged, and all unused drugs should be collected and destroyed.