Transstadial transmission

Transstadial transmission is the persistence of a symbiont or pathogen in an organism from one life stage ("stadium") to the next, such as larva to nymph to adult.

Reasons for this stem from further debate regarding transovarial transmission, described as the passage of a symbiont or pathogen from an infected female to its progeny, especially in eggs.

Outbreaks of emerging infectious diseases have been increasing in frequency as human populations expand and encroach on previously undisturbed or uninhabited areas.

Epidemiologically-relevant transstadial transmission is primarily observed in mites, ticks, and mosquitoes that serve as arthropod vectors of disease.

When the tick engages in its nymphal bloodmeal, B. burgdorferi undergoes many changes in gene expression, upregulating protein generation for use in attachment to the host and establishing infection.

Anaplasma is a bacterial genus causing costly economic losses worldwide, particularly in the food animal agricultural sector.

[22] Transstadial transmission is an important factor in the persistence of microbes in their hosts, particularly within arthropods such as insects, which morph from one life stage to another.

The authors reported finding less bacteria in freshly emerged adult mosquitoes compared to the prior larval stage, significantly influenced by fungal colonization of the hindgut.

The authors hypothesized that physiological and environmental changes associated with fungal colonization, such as less available nutrients and altered pH contributed to the decrease in bacteria from larvae to adult.

[23] Another study evaluated the effect of Aspergillus oryzae fungus on the malaria parasite (Plasmodium berghei) in Anopheles stephensi mosquitoes.