New anthelminthics. Malaysia, are we ready?

In order for one anthelmintic (anti-helmintic drug) to be claimed effective in controlling helminths, the positive effect should be more than 95%. In other words, worm eggs should be reduced by more than 95% after treatments applied.

The first anthelmintic resistant in small ruminants of Malaysia was reported in the 60's, involving the white drench (Benzimidazoles). *Mind you, I'm talking about the resistance of worm in these small ruminants, not the resistance of small ruminants to the drugs.* Later on, resistance was reported towards more groups and during my survey for my masters study, it was found that the government owned farm had animals harbouring resistant worms to ALL THE MAJOR ANTHELMINTIC GROUPS. Worse, they have a programme called 'pawah' where new farmers were given animals to start farming. Yes, they were given animals with resistant worms and this helped in spreading the resistant worms throughout the country.

No, its not the government's fault. Not at all. We never think that this would happen. We thought proper scheduled anthelmintic treatment will kill all the worms and the animals will be worm-free and live happily ever after. We didnt know that underdosing, overdosing the animals during drenching or frequent drenching will effect the natural population of the worms.

Apparently in natural conditions we have resistant worms in small number and these worms were originally susceptible worms, but adapted to the exposure of anthelmintics. When we wipe all the susceptible worms, the remaining resistant worms will be dominant. This is what happened in Malaysia. It was too late when we discover anthelminthic resistance. The resistance level was high, and their populations are high too. In 2005, as far as I remember there was no single farm that still had worm populations susceptible to all 4 anthelmintics tested. In all the farms, the worms showed resistance to at least one anthelmintic. So, at least one drugs cannot be used on each farms as it wont give any significant effect in reducing the worm numbers.

Because of this, farmers were advised to improve their farm managements and encouraged to try other alternatives such as feeding the animals with potential herbal plants such as cassava (Manihot esculenta) and neem (Azadirachta indica) leaves because we are sure that no new anthelmintic will be released soon.

To my surprise, 2 new anthelmintics were recently introduced to the market. What do you expect from this new anthelmintics? For me, I do hope that parasitologist in Malaysia will take a quick action to guide the farmers on using the anthelmintics in a responsible manner. Before the farmers get to know about these drugs by themselves and shove the drugs to their animals, thinking this will solve the resistance problem. The farmers need to be consulted, need to be guided.

The researchers in Australia claimed that resistance to these drugs will occur in 40 years time, but I will just give 10 years for resistance to occur in our beloved country. Or maybe less. Resistance will occur rapidly, especially in our region where blood sucking worm infection is an issue throughout the year. Our climate is like the heaven on earth for them - warm, moist, humid. And because of that, management become more difficult, infections become more severe and normally leads to death.

And to avoid this to happen, farmers rely heavily on drugs and will quickly treat any funny-looking animals without doing any proper diagnosis. Who wants to take the risk of losing their moneyanimals, right?

But the thing is, in our beloved country, in my humble point of view based on my personal experience, we dont have enough labours to do all this consultation to farmers. Yes, we do have veterinary assistant and veterinary attendants. But anthemintic management is a bit tedious, and based on my little experience, even vets didt get the idea right. What do you expect from others?

Things to consider

1. Need to know the worms on the property resistance to what drug(s)? Test should be conducted to test the resistance. Worm egg counts and larval differentials before treatment given and after 10 days treatment applied.

2. Based on the information, identify which drugs still can be used on the worms.

3. The new drugs should be applied together with other drugs with different mode of action. The new drug should not be applied alone as this will lead to resistance.

4. Worm egg count and larval diff should be done before each treatment application. Selective treatment should be applied, not blanket treatment.

And with limited number of staffs in vet service, and most vets are assigned to do all management works, leaving vet assistants and attendants to do most of the customer related job, do you think that we can manage worm resistance? I doubt it.

Seriously, this is not my PhD topic. I should stop ranting. keke.