Synthetic Steroids continued

3. Trenbolone (TbA)

Having a look at Trenbolone really is the start of the more interesting and intriguing side of feed additives and their use and effects in humans. The risk of side effects in humans for this group of drugs is not necessarily through exposure through residue, but rather of the extra label use of drugs meant for production animals. Much of the information below is sourced from websites on the internet, and I must say that the use of steroids in humans is a massive, and sometimes ’underground’ industry, and not a little scary!

Physiology

Testosterone (or synthetic substitutes like TbA) binds to receptors in muscles and stimulates an increase in protein formation, thereby increasing muscle mass, but not increasing fat tissue1.

Use in animals

TbA is a synthetic steroid3 which is used in feedlot animals to improve feed conversion efficiency. It is an androgenic synthetic steroid, unlike the progestagenic steroids (e.g. MGA)1 It can be used alone (in heifers, cull cows and steers) or in combination with estradiol benzoate (EB) (this only in steers and veal calves). When used in combination with EB it can cause a transient increase in sexual behaviour. The growth response to TbA alone can range between 5 and 12% and its duration of effect is 60-90 days. To reiterate from previous issues, the EU has banned the use of hormonal growth promoters in meat production1. In those countries where TbA is not banned it is generally the only androgenic synthetic steroid approved for use in cattle. The side effects of giving TbA in pregnant heifers include increase rate of dystocia, increase in calf mortality, reduced milk yield and masculinisation of foetal female genitalia1. No literature could be found regarding whether or not TbA has been/is used in ostriches, but it has been stated that the use of androgens in poultry species has had conflicting responses, and their use is not currently practical1.

Use in humans

TBA is routinely and in many cases illegally (it is a ‘by prescription only’ drug – Schedule 3 – in the USA4) used by humans for body building and athletic performance reasons. One report accessed indicates that steroids in South Africa are schedule 5 drugs5. Although the human use of the drug is not of any concern to the national residue program as such, it is very interesting due to the fact that some of the more hard core body builders use TbA from veterinary implants meant for feedlot animals. The carcinogenic effect on humans has not been studied sufficiently3 but reproductive consequences of using TbA in humans are likely to be significant, particularly in women. In the South African/ African

sense the other major risk of using injectable steroids is the possible needle transmission of HIV.

References

1. Anon 2005 The Merck Veterinary Manual (9 edn). Merck & Co., Inc, Whitehouse Station, New Jersey, USA

2. Anon 2010 Trenbolone. Wikipedia

3. Scientific Committee on Veterinary Measures relating to Public Health 1999 Assessment of Potential risks to Human Health from Hormone Residues in Bovine Meat and Meat products. Report # XXIV/B3/SC4

4. US Drug Enforcement Agency accessed from http://www.justice.gov/dea

5. SAIDFS (South African Institute for Drug Free Sport) accessed from Canoeing South Africa accessed from www.canoesa.org.za

WESTERN CAPE DEPARTMENT OF AGRICULTURE

VETERINARY SERVICES

Feb 2010 Volume 2, Issue 2

EPIDEMIOLOGY REPORT

What is tested for in the National Residue Program?...cont

2

Vaccinations

SV Species Disease Total Vaccinated SV Beaufort West CANINE RABIES 114

EQUINE AFRICAN HORSE SICKNESS 7

SV Boland CANINE RABIES 1620

FELINE RABIES 161

BOVINE ANTHRAX 438

SV George AVIAN NEWCASTLE DISEASE 300

BOVINE BABESIOSIS 8

CANINE RABIES 130

EQUINE AFRICAN HORSE SICKNESS 236

FELINE RABIES 43

CANINE DISTEMPER 22

SV Malmesbury CANINE RABIES 199

FELINE RABIES 33

OSTRICH NEWCASTLE DISEASE 22

SV Swellendam CANINE RABIES 479

FELINE RABIES 113

AVIAN NEWCASTLE DISEASE 340

SV Vredendal CANINE RABIES 61

EQUINE AFRICAN HORSE SICKNESS 5

OSTRICH NEWCASTLE DISEASE 21

VOLUME 2, ISSUE 2 Page 2

Total vaccinations within the Province: February 2010

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VOLUME 2, ISSUE 2

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VOLUME 2, ISSUE 2

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• The map on Page 4 gives an indication of the Sheep Scab outbreaks and treatments in the Malmesbury District for the summer of 2009/2010. These outbreaks have been widespread and originated from various causes, and they have been the source of much work done by the SV Malmesbury office. The numbers next to the red dots indicate the number of sheep treated in total on each of the farms to date, however there are still ongoing treatments on some of the most currently infected/in-contact farms.

• A positive PRRS serology result early in February prompted an in depth investigation on a farm near Porterville, WC. The investigation consisted of multiple farm visits and sampling, with a total sample count as a result of the suspect case reaching 92 serum samples as well as organ samples from 1 animal taken during slaughter. The farm is a low producer and there was no evidence of clinical signs of PRRS and serology results showed no active sero-conversion by the animals to PRRSV. It is likely that the positive results from the farm were as a result of either a cross reaction or a laboratory associated false positive. It is always important to take into consideration the fact that ALL serological tests do not have 100% sensitivity and specificity, and false positives and negatives should not come as a surprise. The investigation will be concluded once confirmation of antigen tests have been received and the National Department are satisfied with the results. The Epidemiology section wish to thank all AHT’s and SV’s involved in the investigation, your willingness makes all the difference in resolving these matters quickly.

• A positive Brucella herd has been identified in the SV Malmesbury area and standard control and eradication procedures are being followed.

Outbreak Investigations

New/Current Outbreaks and Cases: February 2010

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VOLUME 2, ISSUE 2

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THE BACK PAGE QUESTION

The Epidemiology office has recently been involved in discussions, in both the equine and avian disease testing arena’s, with regard to diagnostic test validation. This is also currently an important topic for the PCR section of the Provincial Veterinary Laboratory. This topic is very complex, with a mixture of simple science and some ‘not so simple’ statistics. This is especially true when validation is required but there are no diagnostic tests to compare data with i.e. Lack of a Gold Standard.

In lieu of this we thought that it will be a opportune time to expose/remind both AHT and SV’s with regards to 2x2 tables, which are an integral part of making epidemiological conclusions. The following example is taken from an article from the British Medical Journal. This article was written to reiterate some questions which must be asked with regards to validity of diagnostic test claims. Greenhalgh, T. 1997 Papers that report diagnostic or screening tests. British Medical Journal 315 (7107): 540+

The following is quoted directly from the text:

“Ten men are awaiting trial for murder. Only three of them actually committed a murder; the seven others are innocent of any crime. A jury hears each case and finds six of the men guilty of murder. Two of the convicted are true murderers. Four men are wrongly imprisoned. One murderer walks free.”

Fill in the 2X2 table below and then work out the Sensitivity, Specificity, Positive Predictive Value,

Negative Predictive Value and the Accuracy of the Jury from the data above.

Notifiable Disease Web Database Update

The implementation of the Notifiable Diseases Web Based database is in full swing. All SV offices have been exposed to the program with the exception of Beaufort West, where this will happen later on in March 2010. Most offices will revert to the new system starting from the 1st March 2010. There have been a few challenges, especially regarding the reliability of the internet in the Malmesbury area. This unreliability prevents the map from loading on the webpage. It does seem that by using Google Chrome as the web browser does improve the speed of the Map downloading. The speed of the system is determined by the individual internet speed, the Elsenburg Server speed as well as the link between the program and the Google Maps application on the internet.

For any enterprising or alternatively bored AHT out there, why don't you find out what the mean age amongst employ-ees per State Vet Office in the Province is, and see if there is a relationship between using web based systems and average age of office? How would one go about filtering out confounding factors such as the Malmesbury internet unre-liability? If you felt that age plays a role in using internet based systems how else could you test for this association.

John Grewar: State Vet Epidemiology Phone: 0218085056 E-mail: JohnG@elsenburg.com

Lugen Govender: Data Processor - Epidemiology Phone: 0218087745

E-mail: LugenG@elsenburg.com

Disclaimer: This newsletter is published on a monthly basis for the purpose of providing up-to-date information regarding epidemiology of animal diseases in the Western Cape Province. Much of the information is therefore preliminary and should not be cited/utilised for publication

True Murderer True Innocent Totals

Jury Guilty a b a+b

Jury Innocent c d c+ d

Totals a+c b+d a+b+c++d