Hookworm timeline
This page is a general guide to what might be expected after inoculation with NA, and should be read in conjunction with the page, Hookworm side effects, and the page section, Therapeutic response.
Individual experience can vary considerably.
Timeline overview
Day 1
Localised skin reaction may occur, and can continue, often intermittently, for a number of weeks. For more detail, see The hookworm inoculation rash.
Days 2-5
The larvae travel, via the lungs and oesophagus, to the intestines. [3] [4] Side effects can occur on or after day 2 and may include respiratory symptoms, fatigue, diarrhoea, cramping, gas, nausea and vomiting, collectively referred to as "worm flu". Symptoms of the disease being treated may also flare. The severity of side effects is dose-dependent, varies widely between individuals and is to some extent determined by the subject’s disease. Side effects are not a reliable indication of a successful outcome from the therapy. See Hookworm side effects.
Days 6-14
The worms mature in the intestines, and this may cause a 'bounce' - a sudden improvement in symptoms, causing subjects to feel unusually well. Starting about three or four days after infection with hookworms, and lasting for up to two weeks, there may be a profound remission of symptoms (Crohn's, allergies, etc.) and also an experience of a strong sense of calm, focus, happiness and lightheartedness, (see The helminthic therapy bounce) but this doesn't last, so don’t stop taking any medications at this point! (See Combining helminthic therapy with drug treatments.)
Weeks 3-11
The worms complete their maturation by 21-22 days and start to attach to the inner wall of the intestine for the first time from day 21. There may be fatigue and gastrointestinal symptoms [5] continuing - often intermittently - from 29-70 days. Due to an increased inflammatory reaction, allergies may get somewhat worse in the first 4-5 weeks, before improving. The worms begin producing eggs between weeks 6 and 8, and some hosts have reported that they experienced the start of long-lasting improvement at 7 or 8 weeks.
Months 3-6
The worms only really begin to 'work', and the reduction in symptoms begins to become consistent, at around 12 weeks. Allergies and asthma, in particular, generally (but not always) resolve between the 11th and 13th weeks. By week 20, the worms are usually in their stride. Where required, a supplementary dose may be added between weeks 12 and 20, but not before week 12.
Months 6-12
By now, the immune system has adjusted to the presence of the hookworms to the point where the good that they do may diminish somewhat, an effect that is usually offset by the addition of supplementary doses.
Months 12-24
A few may not see any benefit until after 12 months, or even as late as 2 years, and there is always a possibility of encountering minor setbacks until 2 years.
Year 2 and beyond
As long as a hookworm colony is maintained, benefits may continue to develop beyond two years, although to an increasingly lesser extent.
The timeline in detail
For details of the developmental stages and migration of NA, see the following page section.
Day 1: Inoculation
For information about the inoculation process, see the following page.
Some people experience an itch and/or a pink rash that can be raised but is limited to the site of inoculation. For more detail about this and how to treat the itch, see the following page.
In a few cases, a lack of any skin response during the first 3 days may indicate that the larvae failed to survive the rigours of the journey, particularly if exposed to extreme cold which is always possible during even a short period at altitude during flight. In this event, the host should contact their provider.
When trying helminthic therapy for the first time, it is easy to obsess about the process, to wonder whether the treatment has 'taken', and to ascribe every tick and sniffle that develops in the first few days, post inoculation, to the helminths. This obsession is natural, but it is important to remember that one's body continues to operate largely as usual in the early stages of a helminthic infection. One still gets colds and food poisoning, etc., and any physical changes experienced by new helminth hosts are far more likely to be manifestations of normal bodily functions than the action of the helminths. The latter follow a natural progression determined by evolution over millions of years, which is largely hidden from immediate experience.
Days 2-5: Migration
During the first two days, the larvae migrate from the skin, via the bloodstream, to the lungs, and, once they are in the bloodstream, they commence feeding on protein within the blood. [6] [7].
The still-invisible larvae then burrow through the lining of the lungs to join all the particulate matter - dust, smoke particles, pollen, etc. - being swept up along the 'escalator' of hairs that lines the inside surface of the lungs. This ciliary conveyor belt eventually transports the larvae to the throat, where they transfer from the airway to the gullet before continuing on their journey down to the stomach and on to the small intestine, where they will spend the remainder of their lives. (See Hookworm lifespan.)
Coughing up phlegm and spitting this out should be resisted from days 2-5 (day 2 beginning 24 hours after inoculation) to avoid expelling larvae that might be passing through the throat at the time. The transfer from airway to oesophagus/esophagus occurs quite low in the throat (beneath the epiglottis) so, while coughing up phlegm from the throat might cause a loss of larvae, blowing one's nose or sneezing should not. However, using a neti pot for nasal irrigation may wash away larvae if this is done by drawing saline in through a nostril and expelling it from the mouth. A more worm-friendly method for use in the first few days after inoculation is to draw in saline through one nostril and immediately expel this via the other nostril without it entering the throat. To further reduce the risk of inadvertently irrigating the throat and consequently losing larvae, the head can be tipped forward to a horizontal position. If any of the rinse solution 'escapes' and starts to trickle down the throat, this should be swallowed rather than being spat out. If this water had gathered up any larvae, swallowing it will just help them on their journey to the stomach.
Common side effects at this stage are, in descending order of occurrence: a flare of the skin rash at the site of inoculation, fatigue, diarrhoea, cramping and gas, nausea and vomiting.
For more detail about the side effects, see Hookworm side effects.
Children may display behavioral changes akin to those seen in a child with flu or allergies - lethargy, crankiness, etc. Symptoms of the disease being treated may flare, and there may be a recapitulation of long-forgotten injuries and illnesses. (See: Recapitulation of old injuries, illnesses.)
Days 6-14: The 'bounce'
Typically, not much happens during this period, unless it is a continuation of symptoms that started within the first few days, although a few may see symptoms begin at this point.
The most noteworthy development at this stage is the possible experience of a 'bounce', which is a fairly unusual phenomenon observed in some self-treaters but not described in the scientific literature.
The ‘bounce’ is a period in which all the subject's usual symptoms (Crohn's, asthma, allergies, etc.) disappear, sometimes completely. It typically occurs around the end of week one, perhaps as early as day five and even as late as week two. It can last about a week, but may appear for only 3-4 days, or, rarely, last for almost two weeks. Often this cessation of symptoms is accompanied by a wonderful feeling of calm, serenity, well-being and happiness.
It is easy to take a ‘bounce’ as evidence that the worms have 'worked' and that all will be well form this point on. Unfortunately, the ‘bounce’ never lasts, so one should not suddenly abandon whatever medications one is taking, or the diet one is following! This phenomenon is only temporary and not an indication that one has achieved remission in record time.
The appearance of a ‘bounce’ may be due to the fact that the body suddenly finds it has an appropriate target at which to aim its immune artillery. Alternatively, it may be due to something that the larvae are doing that elicits a strong response that quells inflammation. Either way, the 'bounce' is something to be enjoyed... while it lasts.
For more detail, see the following page.
Weeks 3-11: Side effects
If side effects are going to be experienced, this is the most likely period for them to appear.
After reaching the small intestine, the larvae moult, complete their maturation by 21-22 days and start to attach to the inner wall of the intestine for the first time from day 21. Initially, the hookworms distribute themselves along the length of the jejunum, unless this has been surgically removed or an individual has hundreds of worms.
There may be fatigue and gastrointestinal symptoms [12] continuing - often intermittently - from 29-70 days. These side effects correlate with the period of elevated eosinophil counts (see the graph below) which can result in eosinophilic gastroenteritis. The side effects peak at about 50 days, before gradually diminishing and returning to baseline at approximately 100 days, although this period can be further prolonged for some, for example to 130 days. [13]
Graphic taken from: Dose-ranging study for trials of therapeutic infection with Necator americanus in humans
Side effects at this stage can include, in order of occurrence: fatigue, cramping, bloating, gas, epigastric pain (stomach ache all over the abdomen) or sometimes pain concentrated on the left side, [14] diarrhoea, nausea, and a recurrence of the skin rash, especially on day twenty-one when the worms begin to attach to the intestines. A few people have reported the appearance of constipation between the 3rd and 10th weeks, and some have noticed a heightened sense of smell from around 5 or 6 weeks. While the latter change is usually welcome, it was linked with nausea in one case. Very rarely, someone may report feeling depressed.
For those individuals who get gastrointestinal side effects, these are most likely to occur around day 21, as a result of the body's attempt to expel the worms by deploying eosinophils - white blood cells that attack helminths - to cause eosinophilic enteritis. However, some only see the start of gastrointestinal symptoms from day 30 onwards.
In most people, this inflammatory response translates to a few days of loose bowel movements or diarrhoea, perhaps accompanied by fatigue. However, a few people may get prolonged gastrointestinal symptoms continuing for many weeks, even beyond week 20, and they may occasionally only start between 10 and 12 weeks.
These side effects always resolve eventually, without treatment.
The severity of the side effects varies enormously from person to person and is dose-dependent. Only a small percentage experience stronger side effects, including pronounced diarrhoea and cramping due to gas, which can be spectacularly bad and has been described as 'toxic', 'industrial' or 'otherworldly'.
Rarer still are fever, night sweats and joint pain. For those suffering the worst side effects, even if it is only a few percent of those who try the therapy, the effect is such that study or work would be very difficult. Therefore care should be taken in optimising dosing, right from the outset. For guidance on this, see the Hookworm dosing and response page.
All the side effects except the skin rash normally reduce sequentially with successive doses. One individual, who had many weeks of diarrhoea following the first hookworm dose, found his symptoms greatly reduced the second time around and, after the third dose, there was no liquid diarrhoea at all during the side effect period, just very soft stools with a 'cow pat' consistency. After the fourth dose, his stools were virtually as normal, but remained slightly softer than they had been prior to infection.
The skin rash at the inoculation site may also recur during the gastrointestinal side effect phase, perhaps because the worms shed cells and debris from their skin as they migrate through the host's skin, and, when the worms attach and put the same kind of material (their skin) into contact with the host's immune system in the intestines, the host's immune system releases antibodies to those types of cells or proteins wherever they occur, whether in the intestine or in the skin.
Apart from the skin rash, which tends to ease after a few days, all the other side effects typically come and go, and the experience can be very much like riding a roller-coaster.
There is also enormous variation between individuals, with some people getting no symptoms at all, and others - especially those using higher doses - experiencing relentless fatigue, disabling abdominal pain and geysers of diarrhoea.
It is also worth bearing in mind that hosting worms does not stop one succumbing to all the usual infections, stomach upsets, etc., to which man is heir, nor prevent adverse reactions to toxic substances or other treatments. So symptoms that emerge following inoculation with helminths may not necessarily be due to the worms, although they can often get the blame simply because they are a new factor.
For more detail about some of the possible side effects and how to treat them, see the following page.
Months 3-6: Maturity
The worms usually start to work - if they are going to work at all - between week 12 and 20, although this varies between individuals and depends on the disease being treated. By week 20, the worms are usually in their stride and, where required, a supplementary dose may be added between weeks 12 and 20, but not before week 12. See Hookworm dosing and response.
Months 6-12
Between six and twelve months, the immune system adjusts to the presence of the hookworms to the point where the good they do may diminish somewhat. For some people, this means that they may fall out of full remission or require continued medication to maintain it, albeit at a lower level than pre-hookworms. The addition of supplementary doses will usually reverse this trend.
Beyond this period of possible drop-off, things get better again, until a final equilibrium is achieved. For some, this may be reached at 11 months, while, for a few, it may take longer.
Months 12-24
A few may not see any benefit until after 12 months, or even as late as 2 years, and those who have seen earlier benefits should continue to note gradual improvement beyond 12 months, while still possibly encountering minor setbacks until 2 years.
Year 2 and beyond
As long as a hookworm colony is maintained, benefits may continue to develop beyond two years, although to an increasingly lesser extent.
Eventually, efficacy will decline as the worms age. This may not be for 3, 4, 5, or even more years, (see Hookworm lifespan) but it is possible for efficacy to decline earlier than this, especially in a small sub-group of individuals with Crohn's disease or one of a few other specific conditions. For these few, efficacy can decline as early as three months, while, for others, it may happen when the egg output of their hookworms declines substantially at about the 12-month mark. Whenever there is a loss of benefit, subjects should immediately arrange to receive a supplementary dose, which will usually quickly restore efficacy.
A few people may continue to experience side effects following supplementary doses. See the following page section.