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The Zygomycetous fungus is reported to
be allergenic. It may cause mucorosis in immune compromised
individuals. It occupies a biological niche similar
to Mucor sp. It is often linked to occupational allergy.
The sites of infection are the lung, nasal sinus, brain,
eye, and skin. Infection may have multiple sites.
Rhizomucor is allergenic, filament-like
fungus, linked to occupational allergy, occupying a
biological status like that of Mucor sp. It is a cosmopolitan
fungus often found in soil and decayed fruit and vegetables.
Rhizomucor species; Rhizomucor pusillus, Rhizomucor
miehei can grow in a temperature as high as fifty four
degrees Celsius and are thermophilic. Rhizomucor variabilis
is close to Mucor hiemalis and is often viewed as its
degenerate culture. It contains three species and to
differentiate them the maximum growth temperature, assimilation
profile, thiamine dependency and diameter of the sporangia
are used.
They have poorly developed structure
called rhizoids at the base of the sporangiophores.
These structures are rudimentary and mostly rare or
difficult to recognize and are on stolons located between
the sporangiophores which are irregularly branched with
sporangia at the apices. The sporangia are round in
shape and broen. They also have culmillae, structures
which support the sporangiophores and they are spherical
or pryiform. Sporangiospores are small one-celled and
round. There are rough-walled round and dark brown zygospores
formed in mating between compatible isolates, in the
aerial hyphae, structures that are nonseptate and broad.
The hyphae can be observed in the infected tissue as
thin walled, non parallel and with irregular branches.
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Rhizomucor Sp is among the group of fungi
that cause the angio-evasive disease called zygomycosis.
Their infection is rare in humans but is extremely fatal
once infected and may cause mucorosis in individuals
with a compromised immune system. It mainly affects
the lung, nasal sinus. Brain, eye and skin and it may
have multiple sites. The feature of this disease that
makes its very frustrating is vascular invasion that
causes necrosis of the infected tissue and may lead
to perineural invasion. Different species of Rhizomucor
affect different people for example Rhizomucor variabilis
infections have been reported in healthy individuals
while infection due to Rhizomucor pusillus, though a
seldom agent of cutaneous pilmonary and disseminated
zygomcosis, has been reported in patients with hematological
diseases and diabetes mellitus. In animals Rhizomucor
commonly causes bovine mycotic abortions
Rhizomucor grow rapidly and mature within
four to five days. The color of the colony at the front
is initially white but turns grayish to yellowish brown
after some time and the reverse is white to pale. Their
texture looks like cotton candy. They seem to be an
intermediate of the Mucor and Rhizopus. They can be
differentiated from Mucor by the fact that they have
the ability to grow in very high temperatures and by
having rhiziods and stolons. They are different from
Rhizopus due to their branched sporangiophores and that
their rhizoids which are not arising opposite of the
sporangiophores. Their broad sporangia and sporangiophores
that are not swollen where they join to the columellae,
makes them distinct from Absidia.
The adverse effects of fungi on human
and animal health calls for caution since the treatment
of Rhizomucor infections is difficult and is therefore
crucial to make early diagnosis since it has a high
mortality rate and the patient may need surgery and
anti-fungal therapy.
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