We have recently been seeing quite a few farms affected by gastrointestinal parasitism.
The problem is mostly due to Haemonchus, the so-called Barber's Pole worm because of the appearance of the adult worms. This worm is a blood-sucker: the larvae set up camp in the 3rd stomach compartment where they grow into adults and then pass large numbers of eggs. Both the adults and larvae can cause severe anaemia in alpacas such that worm egg counts may not be spectacularly high but anaemia may be significant.
This "summer's" wet and mild weather conditions have meant that parasites have had perfect conditions for survival on the pasture which is why we are probably seeing so many problems at the moment. I would like to encourage you to check your animals this weekend: check their body condition and also check their colour to see if they appear anaemic or not. The best way to do this is to evert the lower eyelid using one thumb while gently depressing the eye through the upper eyelid with the other thumb, causing the third eyelid to protrude. Normally these mucous membranes are pink and healthy-looking: the whiter they are, the worse the anaemia may be. Anaemic animals will also be quieter than normal and may move more slowly than healthy alpacas.
If you suspect that you may have a problem, please call your vet and/or check faecal egg counts to assess the situation. The problem is likely to be worse if you have higher stocking densities and larger numbers of susceptible animals, but smaller units can also be affected.