Astrakhan Spotted Fever: Disease Characteristics Research Report

Target: Astrakhan spotted fever (MONDO:0024473) · Category: Infectious Disease · Report date: 2026-09-28

Scope note on sources. Astrakhan spotted fever (ASF) has a small literature, much of it Russian-language with English abstracts only. The surveillance numbers below come from one 1983–1988 prospective series (as summarized in the Parola 2005 review), one 2000–2020 registry summary (a 2021 conference abstract), and a 2022 serology study that quotes official annual counts. Quotations marked verbatim were copied from PubMed abstracts retrieved during this research; figures attributed to the 2024 China letter and the 2021 IJID abstract were read from indexed summaries because the publisher pages were paywalled, and should be re-verified against the full text before being used as evidence snippets.

1. Disease Information

Overview. Astrakhan spotted fever is a tick-borne spotted-fever-group (SFG) rickettsiosis caused by Rickettsia conorii subsp. caspia, a member of the R. conorii complex. It is endemic to the lower Volga delta and Caspian littoral (Astrakhan oblast and Kalmykia, Russia), transmitted chiefly by Rhipicephalus pumilio and the brown dog tick Rhipicephalus sanguineus, and presents as a summer febrile exanthem that resembles Mediterranean spotted fever (MSF) but with a notably lower frequency of inoculation eschar. The Kosovo tick study describes it as "a summer spotted fever resembling Mediterranean spotted fever, endemic in Astrakhan, a region of Russia located by the Caspian sea" (verbatim, PMID:12860620).

The disease was first noticed in the 1970s as a "viral exanthema of unknown etiology" and shown to be a rickettsiosis in the early 1990s: "The acute febrile disease with characteristic rash seen in Astrakhan region and named as 'viral exanthema of unknown etiology' was proved to be a spotted fever group rickettsiosis" (verbatim, Tarasevich 1991, PMID:1884783). Russian surveillance dates recognition to 1983: "Astrakhan spotted fever, caused by R. conorii subsp. caspia has been recognized since 1983" (verbatim, Tarasevich 2006, PMID:17114680).

Identifiers

Synonyms: Astrakhan fever; Astrakhan rickettsial fever (ARF, used by Russian and Chinese authors); Astrakhan fever rickettsiosis; historically "viral exanthema of unknown etiology" (Astrakhan). Agent synonyms: Astrakhan fever rickettsia (AFR); R. conorii Astrakhan strain; type strain A-167.

Nature of the information. All data are aggregated disease-level resources and case series, not individual EHR records.

2. Etiology

Causal factor. Infection with R. conorii subsp. caspia following the bite of an infected Rhipicephalus tick. Taxonomy: Zhu et al. (2005) proposed "R. conorii subspecies caspia subsp. nov. (type strain = A-167)" on the basis of multilocus sequence typing, multi-spacer typing and mouse serotyping, noting that "strains within the R. conorii species show MST genotypic, serotypic, and epidemio-clinical dissimilarities" (verbatim, PMID:15766388). Earlier work had found the agent antigenically indistinguishable from the Israeli spotted fever rickettsia: "Astrakhan fever rickettsiae were found to be serologically and antigenically similar to Israeli spotted fever rickettsiae. Both of them probably belong to a single Rickettsia conorii pathotype complex. Only PFGE pattern analysis could clearly discriminate Astrakhan fever rickettsiae from other isolates" (verbatim, Eremeeva 1994, PMID:7985764; see also Drancourt 1992, PMID:1583342, a letter titled "Astrakhan fever rickettsia is identical to Israel tick typhus rickettsia").

Risk factors (environmental / behavioural). - Tick exposure and dog contact. In the 1983–1988 series, "Most of the patients had dogs and reported having contact with Rhipicephalus sanguineus dog ticks" (Parola 2005 review, PMID:16223955, summarizing Tarasevich). Tarasevich (1991) detected SFG rickettsiae "in 8 of 104 Rhipicephalus sanguineus ticks removed from dogs" (verbatim, PMID:1884783). - Season. 85% of cases occurred in summer, 43% in August alone (PMID:16223955). The 2019 serology cohort was collected May–October (PMID:35467375); the four Chinese cases all began in July 2023 (PMID:38462076). - Rural residence in the Volga delta / Caspian steppe. Early cases were "in patients of rural areas" (PMID:16223955). The 2021 registry abstract reports spread from Astrakhan city plus 3 districts in 1993 to all 11 districts of the oblast by 2013 (IJID 2021 abstract, PII S1201-9712(21)01194-2). - Age and sex. Adults (94%) and males (61%) predominated in 1983–1988 (PMID:16223955). The 2019 cohort spanned ages 1–88 (mean 45) (PMC9241626). - Vector abundance. The 2021 abstract states the rise in incidence "begins when the abundance index of R. pumilio ticks reaches its maximum" (indexed summary; verify against full text).

Genetic risk / protective factors. None reported for ASF. No GWAS, ClinVar, or ClinGen data exist. This is expected for an acute zoonotic infection.

Protective factors. Tick avoidance and prompt tick removal (generic to SFG rickettsioses; CDC 2016 guidance, PMID:27172113). No vaccine exists (PMID:24059918: "No suitable vaccines for human use are currently available to prevent rickettsial diseases", verbatim).

Gene–environment interactions. Not studied.

3. Phenotypes

Frequencies are from the 1983–1988 prospective series of 321 cases (as summarized in PMID:16223955) unless stated otherwise. HPO identifiers below were read from the repository's HP term cache (cache/hp/terms.csv) during this session.

Supporting quotes (verbatim): - "The disease presented with long-term fever (body temperature 39-40 degrees C), intoxication, conjunctivitis, hepatomegaly, regional lymphadenitis, disseminated roseolous papular-hemorrhagic rash, arterial hypotension." (Galimzianov 1996, PMID:9324803) - "the

Astrakhan Spotted Fever: Disease Characteristics Research Report

Target: Astrakhan spotted fever (MONDO:0024473) · Category: Infectious Disease · Report date: 2026-09-28

Scope note on sources. Astrakhan spotted fever (ASF) has a small literature, much of it Russian-language with English abstracts only. The surveillance numbers below come from one 1983–1988 prospective series (as summarized in the Parola 2005 review), one 2000–2020 registry summary (a 2021 conference abstract), and a 2022 serology study that quotes official annual counts. Quotations marked verbatim were copied from PubMed abstracts retrieved during this research; figures attributed to the 2024 China letter and the 2021 IJID abstract were read from indexed summaries because the publisher pages were paywalled, and should be re-verified against the full text before being used as evidence snippets.

1. Disease Information

Overview. Astrakhan spotted fever is a tick-borne spotted-fever-group (SFG) rickettsiosis caused by Rickettsia conorii subsp. caspia, a member of the R. conorii complex. It is endemic to the lower Volga delta and Caspian littoral (Astrakhan oblast and Kalmykia, Russia), transmitted chiefly by Rhipicephalus pumilio and the brown dog tick Rhipicephalus sanguineus, and presents as a summer febrile exanthem that resembles Mediterranean spotted fever (MSF) but with a notably lower frequency of inoculation eschar. The Kosovo tick study describes it as "a summer spotted fever resembling Mediterranean spotted fever, endemic in Astrakhan, a region of Russia located by the Caspian sea" (verbatim, PMID:12860620).

The disease was first noticed in the 1970s as a "viral exanthema of unknown etiology" and shown to be a rickettsiosis in the early 1990s: "The acute febrile disease with characteristic rash seen in Astrakhan region and named as 'viral exanthema of unknown etiology' was proved to be a spotted fever group rickettsiosis" (verbatim, Tarasevich 1991, PMID:1884783). Russian surveillance dates recognition to 1983: "Astrakhan spotted fever, caused by R. conorii subsp. caspia has been recognized since 1983" (verbatim, Tarasevich 2006, PMID:17114680).

Identifiers

Synonyms: Astrakhan fever; Astrakhan rickettsial fever (ARF, used by Russian and Chinese authors); Astrakhan fever rickettsiosis; historically "viral exanthema of unknown etiology" (Astrakhan). Agent synonyms: Astrakhan fever rickettsia (AFR); R. conorii Astrakhan strain; type strain A-167.

Nature of the information. All data are aggregated disease-level resources and case series, not individual EHR records.

2. Etiology

Causal factor. Infection with R. conorii subsp. caspia following the bite of an infected Rhipicephalus tick. Taxonomy: Zhu et al. (2005) proposed "R. conorii subspecies caspia subsp. nov. (type strain = A-167)" on the basis of multilocus sequence typing, multi-spacer typing and mouse serotyping, noting that "strains within the R. conorii species show MST genotypic, serotypic, and epidemio-clinical dissimilarities" (verbatim, PMID:15766388). Earlier work had found the agent antigenically indistinguishable from the Israeli spotted fever rickettsia: "Astrakhan fever rickettsiae were found to be serologically and antigenically similar to Israeli spotted fever rickettsiae. Both of them probably belong to a single Rickettsia conorii pathotype complex. Only PFGE pattern analysis could clearly discriminate Astrakhan fever rickettsiae from other isolates" (verbatim, Eremeeva 1994, PMID:7985764; see also Drancourt 1992, PMID:1583342, a letter titled "Astrakhan fever rickettsia is identical to Israel tick typhus rickettsia").

Risk factors (environmental / behavioural). - Tick exposure and dog contact. In the 1983–1988 series, "Most of the patients had dogs and reported having contact with Rhipicephalus sanguineus dog ticks" (Parola 2005 review, PMID:16223955, summarizing Tarasevich). Tarasevich (1991) detected SFG rickettsiae "in 8 of 104 Rhipicephalus sanguineus ticks removed from dogs" (verbatim, PMID:1884783). - Season. 85% of cases occurred in summer, 43% in August alone (PMID:16223955). The 2019 serology cohort was collected May–October (PMID:35467375); the four Chinese cases all began in July 2023 (PMID:38462076). - Rural residence in the Volga delta / Caspian steppe. Early cases were "in patients of rural areas" (PMID:16223955). The 2021 registry abstract reports spread from Astrakhan city plus 3 districts in 1993 to all 11 districts of the oblast by 2013 (IJID 2021 abstract, PII S1201-9712(21)01194-2). - Age and sex. Adults (94%) and males (61%) predominated in 1983–1988 (PMID:16223955). The 2019 cohort spanned ages 1–88 (mean 45) (PMC9241626). - Vector abundance. The 2021 abstract states the rise in incidence "begins when the abundance index of R. pumilio ticks reaches its maximum" (indexed summary; verify against full text).

Genetic risk / protective factors. None reported for ASF. No GWAS, ClinVar, or ClinGen data exist. This is expected for an acute zoonotic infection.

Protective factors. Tick avoidance and prompt tick removal (generic to SFG rickettsioses; CDC 2016 guidance, PMID:27172113). No vaccine exists (PMID:24059918: "No suitable vaccines for human use are currently available to prevent rickettsial diseases", verbatim).

Gene–environment interactions. Not studied.

3. Phenotypes

Frequencies are from the 1983–1988 prospective series of 321 cases (as summarized in PMID:16223955) unless stated otherwise. HPO identifiers below were read from the repository's HP term cache (cache/hp/terms.csv) during this session.

Supporting quotes (verbatim): - "The disease presented with long-term fever (body temperature 39-40 degrees C), intoxication, conjunctivitis, hepatomegaly, regional lymphadenitis, disseminated roseolous papular-hemorrhagic rash, arterial hypotension." (Galimzianov 1996, PMID:9324803) - "the presence of a tache noire was reported in only 23% of the patients" (Parola 2005, PMID:16223955). - "Examination of immunocompetent cells has revealed suppression of T- and B-immunity for 2 weeks in moderate AF and 3 weeks in severe AF. The number of T-helpers was low for 3 weeks while of T-suppressors rose beginning from week 2." (Kasimova 2002, PMID:12498120)

Distinguishing feature vs MSF. The low eschar rate (23%) is the clinically important contrast with Mediterranean spotted fever, where the tache noire is usual. This shifts differential weight toward rash-plus-fever presentations without a findable bite site.

Severity and quality of life. Severe disease accounted for 5.3% of Russian cases and case fatality is stated as approximately 1–2%, with a first reported death in 2013 (figures cited in the 2024 China letter, PMID:38462076; read from indexed summaries, not the full text). No EQ-5D, SF-36 or PROMIS data exist for ASF; as a self-limited acute illness it has no documented chronic quality-of-life burden.

4. Genetic / Molecular Information

Host genetics: not applicable. ASF has no causal genes, pathogenic variants, modifier genes, epigenetic signature or chromosomal abnormality. No ClinVar, HGMD, gnomAD or DECIPHER content pertains.

Pathogen genomics. The genome of R. conorii subsp. caspia strain A-167 was sequenced in 2012 (Sentausa et al., PMID:22887666, J Bacteriol): draft genome of 1,260,331 bases in 25 contigs at ~20× coverage, "a total complement of 1,210 genes (1,636 open reading frames [ORFs])" (verbatim), 33% GC, deposited as GenBank AJUR00000000. Among predicted genes, "820 (67.8%) are complete genes, 229 (18.9%) are split into two to 12 ORFs, and 78 (6.5%) are present only as fragments" (verbatim) — the split/fragmented pattern is the genome-reduction signature typical of Rickettsia.

Typing loci used for identification. 16S rDNA, gltA (citrate synthase), ompA (rOmpA), ompB, sca4, and the 23S–5S intergenic spacer. Pairwise similarity across the four R. conorii subspecies ranged 98.2–100% depending on locus, with ompA and ompB the most discriminating (PMID:15766388). Historic methodology: Roux 1997 (gltA, PMID:9103608), Fournier 1998 (rOmpA, PMID:9734038), Roux 1995 (16S rDNA, PMID:8525055).

Suggested annotations: the surface adhesins rOmpA and rOmpB (UniProt R. conorii entries; Sca family autotransporters) and Sca2/RickA for actin-based motility are the functionally characterized proteins, all studied in R. conorii sensu lato rather than in subsp. caspia specifically.

5. Environmental Information

Infectious agent. Rickettsia conorii subsp. caspia (NCBITaxon:302011), an obligate intracellular Gram-negative alphaproteobacterium of the spotted fever group.

Vectors. - Rhipicephalus pumilio (NCBITaxon:127007) — the principal Astrakhan vector; infection prevalence 3% in Astrakhan-region ticks: "Rh. pumilio from the Astrakhan region were infected with ... the Astrakhan fever agent (3%)" (verbatim, Rydkina 1999, PMID:10603217). The primary-lesion study attributes the bite to R. pumilio (PMID:9324803). - Rhipicephalus sanguineus (NCBITaxon:34632), the brown dog tick — vector in Kosovo, France and Zambia; also implicated by dog contact in Astrakhan.

Reservoirs and hosts. Domestic dogs (Canis lupus familiaris, NCBITaxon:9615) are the principal tick host linking vector to humans. I found no published evidence for a hedgehog or rodent reservoir specific to R. conorii subsp. caspia; a Kazakhstan rodent survey detected R. raoultii, R. slovaca and R. conorii but did not report subsp. caspia in rodents (PMID:36050456).

Geographic distribution beyond Astrakhan.

Non-infectious environmental and lifestyle factors. None established beyond outdoor/rural exposure, dog ownership and season. No toxicological (CTD, EPA) contribution.

6. Mechanism / Pathophysiology

Important caveat. No mechanistic study has been performed on R. conorii subsp. caspia itself apart from cell-culture growth experiments. The chain below is the established SFG rickettsiosis mechanism, documented mainly for R. conorii sensu lato and R. rickettsii, applied to ASF by subspecies membership. Every step from 3 onward should be curated as directness: INDIRECT for ASF, or cited to the pan-rickettsial reviews (Walker 2008, PMID:18414502; Sahni 2013, PMID:24059918) with evidence_source: OTHER or IN_VITRO as appropriate. The two ASF-specific mechanistic observations are the primary-lesion histology (PMID:9324803) and the cytokine/cellular-immunity studies (PMID:12459842, PMID:12498120).

Ordered causal chain

1. An infected Rhipicephalus pumilio or Rh. sanguineus nymph or adult attaches and feeds on human skin, which leads to inoculation of R. conorii subsp. caspia into the dermis with tick saliva. (Demonstrated for ASF by vector isolation and bite-site histology, PMID:9324803, PMID:7985764.)
2. Local replication in the dermis results in a focal necrotizing lesion at the bite site, the primary affect or tache noire, with regional lymphatic drainage leading to regional lymphadenitis. (ASF-specific: PMID:9324803. Note this step completes in only ~23% of ASF patients, PMID:16223955 — a genuine branch point, and an unexplained one.)
3. Rickettsiae adhere to and invade vascular endothelial cells via Sca-family outer-membrane adhesins (rOmpA/rOmpB) engaging host receptors, which results in induced-phagocytosis entry. (Pan-rickettsial; Walker 2008, PMID:18414502; Sahni 2013, PMID:24059918. Inferred for subsp. caspia.)
4. Phagosomal escape into the cytosol leads to intracytoplasmic replication and actin-based motility, which results in cell-to-cell spread without extracellular exposure. (Pan-rickettsial; Sahni 2013 names "intracytoplasmic niche within the host cell, predilection for infection of microvascular endothelium in mammalian hosts" (verbatim) and "motility" among the field's characterized mechanisms.)
5. Haematogenous and lymphatic dissemination leads to multifocal infection of microvascular endothelium in skin, liver, lymph node and other organs.
6. Endothelial infection results in endothelial activation, cytokine release (IL-1, TNF) and leukocyte recruitment. (ASF-supporting: "Comparative study of interleukin-1 and tumor necrosis factor production under conditions of experimental rickettsial infection caused by agents of Astrakhan spotted fever and North Asian scrub typhus showed that therapy with galavit reduced manifestations of the disease, decreased mortality of experimental animals, and decreased the concentrations of interleukin-1 and tumor necrosis factor to normal values" — verbatim, PMID:12459842, evidence_source MODEL_ORGANISM.)
7. Branch A — cutaneous. Dermal microvascular injury and perivascular lymphohistiocytic infiltration produce the disseminated maculopapular and, where injury is greater, petechial/hemorrhagic rash. (ASF: PMID:9324803.)
8. Branch B — systemic. Widespread endothelial injury with increased vascular permeability leads to hypotension, and in a minority to severe multi-organ disease. (ASF: arterial hypotension, PMID:9324803; severe disease 5.3%, PMID:38462076 as indexed.)
9. Branch C — hepatic/reticuloendothelial. Infection of hepatic and splenic microvasculature and reticuloendothelial activation result in hepatomegaly. (ASF: PMID:9324803.)
10. Branch D — immunological. Acute infection is accompanied by transient suppression of T- and B-cell compartments lasting 2 weeks in moderate and 3 weeks in severe disease, with depressed T-helper numbers and a persistently low helper/suppressor index. (ASF-specific human data, PMID:12498120.)
11. Effective antirickettsial therapy (doxycycline) arrests intracellular replication, leading to defervescence and resolution; in its absence severe disease and death occur in a small fraction.

Ontology suggestions (identifiers verified against the repository term caches this session)

Molecular profiling. No transcriptomic, proteomic, metabolomic, lipidomic, single-cell or spatial data exist for ASF. No GEO, PRIDE, MetaboLights or DepMap datasets were found for R. conorii subsp. caspia. This is a real and total gap, not an omission of this report.

7. Anatomical Structures Affected

• Primary target tissue: vascular endothelium of the microcirculation — UBERON:0001981 blood vessel; cell type CL:0000115 endothelial cell.
• Skin: the bite-site primary lesion and the generalized exanthem — UBERON:0002097 skin of body; UBERON:0002067 dermis.
• Lymphatic: regional lymphadenitis draining the bite site — UBERON:0000029 lymph node.
• Liver: hepatomegaly — UBERON:0002107 liver. Spleen involvement (UBERON:0002106) is plausible by analogy with MSF but was not named in the ASF abstracts retrieved.
• Eye: conjunctivitis in 32% — UBERON:0001811 conjunctiva.
• Body systems: cardiovascular (primary), integumentary, lymphatic/immune, hepatobiliary.
• Subcellular: the bacterium occupies the host cytosol (GO:0005829 cytosol) after phagosomal escape; no organelle-specific pathology is described.
• Lateralization: the eschar and its regional adenopathy are unilateral, at the bite site; the exanthem is bilateral and generalized, described as involving the extremities.

8. Temporal Development

• Onset: acute, in previously healthy adults of any age (1–88 years in the 2019 cohort, mean 45; PMC9241626). No congenital or pediatric-specific form. 94% of the historical series were adults.
• Incubation: not stated in the ASF abstracts retrieved; SFG rickettsioses generally run 2–14 days from tick bite. Treat as unverified for ASF.
• Course: a self-limited acute febrile illness of roughly 1–2 weeks with treatment. Fever is described as "long-term" at 39–40 °C (PMID:9324803). The primary lesion precedes or accompanies fever onset where present.
• Stages: no formal staging system exists. Severity is graded clinically as moderate versus severe in the Russian literature (63 moderate vs 12 severe of 75 patients, PMID:12498120).
• Immunological recovery lags clinical recovery: lymphocyte suppression persists 2–3 weeks and the helper/suppressor index "remains low till the end of the disease" (verbatim, PMID:12498120).
• Critical intervention window: early empiric doxycycline. The CDC states this generally for tickborne rickettsial disease: "early empiric antibacterial therapy can prevent severe disease and death" (verbatim, PMID:27172113).
• Chronicity / relapse: no chronic or relapsing form is reported. Serological IgM and IgA are detectable from day 1 to day 16 of illness (PMC9241626).

9. Inheritance and Population

Inheritance: not applicable. ASF is an acquired infection with no heritable component, no penetrance/expressivity/anticipation/mosaicism/founder-effect/carrier-frequency parameters.

Epidemiology

For dismech Prevalence records, the 23.18 per 100,000 figure is a regional ANNUAL_INCIDENCE averaged over 2000–2020 and needs rate_denominator: POPULATION_PER_YEAR; the ~200–300 national annual counts are CASES_IN_LITERATURE-adjacent registry counts, not a rate.

Demographics. Male predominance (61%) and adult predominance (94%) in the 1983–1988 series (PMID:16223955) most plausibly reflect exposure rather than susceptibility. Sex ratio ≈ 1.6:1 male:female.

Geographic trend. Endemic area expanded within Astrakhan oblast from the city plus 3 districts (1993) to 9 rural districts plus the city (1999) to all 11 districts (2013), with incidence peaks in 2000, 2002, 2005–2007 and a maximum in 2013 tracking R. pumilio abundance (IJID 2021 abstract, indexed summary).

10. Diagnostics

Serology (the mainstay). - Microimmunofluorescence (MIF) against SFG antigens. ASF sera react to the homologous Astrakhan strain and to the Israeli isolate similarly, and differently from R. conorii Malish: "The serologic response to specific rickettsial agent and to Israelian isolate has been found to be similar, but was different of that to R. conorii. Immunoglobulin G (IgG) and IgM antibodies were detected in most sera and were directed against the lipopolysaccharide" (verbatim, PMID:8549703). - ELISA IgM alone is insufficient. In 185 patients, "the determination of IgM alone allows for serological confirmation of diagnosis in only 46.5% of cases but ... the determination of both IgM and IgA increases this rate to 66.5%" (verbatim, PMID:35467375). IgM recognized both LPS and proteins; IgA predominantly proteins. This is the most actionable recent diagnostic finding for ASF and argues for adding IgA to the panel. - Complement fixation was used historically, cross-reacting across R. conorii, R. akari and R. sibirica at titres 20–640 (PMID:1884783) — insufficiently specific by modern standards. - Retrospective serosurveillance in high-risk areas: Chekanova 2019, PMID:31200408.

Molecular. - PCR amplification and sequencing of gltA, ompA, 16S rDNA, ompB, sca4 and the 23S–5S spacer distinguishes subspecies (PMID:12860619, PMID:12860620, PMID:28986641). - Suicide PCR on skin biopsy specimens is validated for rickettsioses generally (Fournier 2004, PMID:15297478) and is the route to a diagnosis from an eschar or rash biopsy. - Real-time pan-Rickettsia PCR for screening, with MLST confirmation.

Culture. Isolation in cell culture or guinea pigs is possible but slow, low-yield and biosafety-restricted; early attempts recovered rickettsiae in 2 of 12 cell-culture samples and seroconverted 4 of 8 guinea pigs (PMID:1884783). Strains A-108 and A-167 came from R. pumilio haemolymph (PMID:7985764).

Laboratory findings. Cellular immunology shows transient lymphopenia-like suppression with neutrophil increase from week 2–3 (PMID:12498120). Routine haematological and hepatic abnormality frequencies for ASF were not available in the retrieved abstracts.

Imaging, electrophysiology, functional tests: no role.

Genetic testing: not applicable (host).

Differential diagnosis. Mediterranean spotted fever (R. conorii subsp. conorii), Israeli spotted fever (subsp. israelensis, serologically near-identical — the key laboratory pitfall), Siberian tick typhus (R. sibirica), R. massiliae and R. aeschlimannii infection, Crimean-Congo hemorrhagic fever (co-circulating in the Caspian region and a critical rule-out given the hemorrhagic rash), West Nile fever, hemorrhagic fever with renal syndrome, and non-rickettsial viral exanthems. The 2022 study makes the general point: "The symptoms of this bacterial infection are similar to those of viral infection, and thus, diagnostic accuracy has special clinical importance" (verbatim, PMID:35467375). Butenko 1995 (PMID:7476689) treats arbovirus infections, HFRS and Astrakhan fever together as the regional differential.

Screening. No population screening. Surveillance is clinician-reported case notification plus tick-abundance monitoring.

11. Outcome / Prognosis

• Mortality: approximately 1–2%, with severe cases 5.3% of those infected and a first reported death in 2013 (cited in PMID:38462076; verify in full text before use as an evidence snippet).
• Recovery: the great majority recover fully with antibiotic therapy; ASF is self-limited and leaves no documented chronic sequelae.
• Prognostic factors: delay to effective antibiotic therapy is the dominant modifiable factor across SFG rickettsioses (PMID:27172113). Severity correlates with depth and duration of cellular immunosuppression (PMID:12498120), though that is an association in a small series, not a validated prognostic marker.
• Prognostic biomarkers: none validated. IL-1 and TNF concentrations tracked disease manifestations in an animal model (PMID:12459842) but have not been evaluated prognostically in patients.
• Survival statistics, DALYs, disability outcomes, QOL instruments: no ASF-specific data in SEER-equivalent, GBD or ICF sources.

12. Treatment

Doxycycline is the treatment of choice. The CDC recommendation for tickborne rickettsial disease is explicit: "doxycycline is the treatment of choice for suspected tickborne rickettsial diseases in adults and children" (verbatim, PMID:27172113). For ASF specifically, a comparative Russian series concluded "Doxycycline efficiency was higher than that of rifampicin" (verbatim, PMID:12498120) — a direct head-to-head observation in ASF patients and the strongest disease-specific therapeutic evidence available.

The NCIT identifiers above were not resolvable in this worktree's cache/ncit/terms.csv during this session (the grep returned nothing), so each must be verified with just validate-terms before being written into a KB entry. Per the repository's term contract, do not commit an NCIT CURIE from this table without that lookup.

Adjunctive interferon — historical, and not recommended. Galimzianov 1996 reported that "Adjuvant use of interferons in basic treatment of Astrakhan fever elevates its efficacy" with alpha-2 at 15,000–25,000 IU/kg/day and gamma at 1,500–2,500 IU/kg/day, while noting that "Interferons induce side effects early in the course: intensification of hyperthermia and pains" (verbatim, PMID:8771664). This is a single uncontrolled 1996 report and has no modern support; curate it as historical practice, not current therapy.

Immunomodulation in animals. Galavit reduced IL-1/TNF and mortality in experimental ASF infection (PMID:12459842) — evidence_source: MODEL_ORGANISM, no human translation.

In vitro antimicrobial work. Wild thyme and bergamot essential oils inhibited R. conorii caspia growth in Vero cells (PMID:30316918); chitosan, selenium and silver nanoparticles showed anti-rickettsial activity in Vero cells (PMID:41011786, 2025). Both are IN_VITRO and pre-clinical.

Not applicable: gene therapy, cell therapy, RNA therapeutics, targeted therapy, immunotherapy, surgery, rehabilitation. No registered clinical trials for ASF were found; a ClinicalTrials.gov query was not run this session and the absence should be confirmed before asserting it in an entry.

Pharmacogenomics: none described.

13. Prevention

• Primary prevention: tick-bite avoidance — protective clothing, repellents, prompt full-body tick checks and early removal after outdoor exposure in the endemic season (May–October, peak August). Dog-directed measures matter disproportionately here because Rh. sanguineus is a domestic, peridomestic and indoor-capable tick: acaricidal collars and treatments for dogs, and control of tick infestations inside dwellings. The French urban family cluster is the cautionary case — ticks were "collected from the floor from behind the furniture" inside the home (verbatim, PMID:23140893).
• Immunization: no vaccine exists for any Rickettsia in human use (PMID:24059918).
• Chemoprophylaxis: not recommended after tick bite for SFG rickettsioses; the CDC approach is watchful waiting with early empiric treatment on symptom onset (PMID:27172113).
• Secondary prevention: clinician awareness in endemic areas so that fever plus rash in summer triggers empiric doxycycline before serological confirmation, since early treatment prevents severe outcomes. The Kazakhstan surveillance work makes the analogous point for its own region: "Kazakh physicians should be aware of rickettsioses after tick bites in both regions studied" (verbatim, PMID:31053085).
• Public health: vector surveillance tied to R. pumilio abundance indices, which the Astrakhan registry analysis links to incidence peaks; stray-dog population management; health education before the summer season.
• Genetic counseling / carrier or prenatal screening: not applicable.

14. Other Species / Natural Disease

• Vectors (not diseased hosts): Rhipicephalus pumilio NCBITaxon:127007; Rhipicephalus sanguineus NCBITaxon:34632.
• Dogs (Canis lupus familiaris, NCBITaxon:9615) are the key tick-maintenance host. Whether dogs develop clinical disease from R. conorii subsp. caspia was not addressed in any retrieved source; canine infection with R. conorii sensu lato is documented generally. Treat canine clinical disease as unestablished for this subspecies.
• Zoonotic status: ASF is a tick-borne zoonosis with no human-to-human transmission.
• No OMIA record applies — this is an infectious disease, not an inherited animal disorder.
• Comparative pathology: the endothelial tropism of SFG rickettsiae is conserved across mammalian hosts (Walker 2008, PMID:18414502).
• Incidental tick findings in other taxa: R. conorii subsp. caspia has been detected in Rh. sanguineus on dogs in Kosovo, France and Zambia; a Formosan pangolin tick survey (PMID:27426438) and a Turkish cattle tick survey (PMID:35631021) appear in the same literature searches but the retrieved abstracts do not establish subsp. caspia detection in those studies.

15. Model Organisms

• Cell culture (principal system). Vero cells are the standard host for R. conorii caspia propagation and antimicrobial testing (PMID:30316918; PMID:41011786). Historic isolation used cell cultures with immunofluorescence detection (PMID:1884783). evidence_source: IN_VITRO.
• Guinea pig (Cavia porcellus, NCBITaxon:10141). Used for isolation and seroconversion in the original ASF characterization: 4 of 8 inoculated animals developed SFG antibodies (PMID:1884783). A classical rickettsial isolation host, not a fidelity model of human disease.
• Mouse (Mus musculus, NCBITaxon:10090). Used for serotyping, not pathogenesis: mouse serotyping distinguished the Chad isolate from other R. conorii complex members by a specificity difference of 2 (PMID:12860619) and underpinned the subspecies proposal (PMID:15766388).
• Experimental infection for immunopathology. The IL-1/TNF and galavit work used unspecified "experimental animals" (PMID:12459842); the species is not stated in the abstract and should be read from the full text before curation.
• Genetic models: none. No knockout, transgenic, humanized, organoid or iPSC model exists for ASF, and none is expected — the relevant genetics is bacterial, and Rickettsia is genetically intractable relative to free-living bacteria.
• Limitations. No animal model reproduces the human ASF clinical picture, including the eschar-poor rash phenotype that distinguishes ASF from MSF. Any modeled_mechanisms link for these systems should carry fidelity: LOW or UNKNOWN, model_scale: MOLECULAR or CELLULAR for the Vero work, and an explicit divergences entry of type SPECIES_MISMATCH (guinea pig, mouse) or BOUNDARY_OMISSION (Vero cells contain no vasculature, no immune compartment, and cannot report rash or hypotension).

Evidence Inventory for Curation

Verified PMIDs with abstracts retrieved this session, suitable for just fetch-reference:

Figures needing full-text verification before use as snippets: the 321-case series percentages (94% adults, 61% male, 85% summer, 43% August, 94% fever with rash, 23% eschar, 32% conjunctivitis) read from the Parola 2005 review rather than the primary Russian source; the 4,894 cases and 23.18 ± 1.5 per 100,000 from the 2021 IJID conference abstract; and the 5.3% severe / 1–2% mortality / first-death-2013 figures cited in the 2024 China letter. The last three publisher pages returned 403 or CAPTCHA this session.

Sources

• Proposal to create subspecies of Rickettsia conorii (PMID:15766388)
• Detection of Astrakhan fever rickettsia from ticks in Kosovo (PMID:12860620)
• Isolation of a rickettsia related to Astrakhan fever rickettsia in Chad (PMID:12860619)
• Diagnostic Value of IgA Antibody Measurement in ARF (PMID:35467375)
• Genome Sequence of R. conorii subsp. caspia (PMID:22887666)
• Tick-Borne Rickettsioses around the World (PMID:16223955)
• Update on Tick-Borne Rickettsioses: a Geographic Approach
• Emergence of Astrakhan rickettsial fever in China (PMID:38462076)
• Epidemiological monitoring of the natural focus of Astrakhan spotted fever (IJID 2021)
• Urban family cluster linked to Rh. sanguineus infected with R. conorii subsp. caspia (PMID:23140893)
• First detection of R. conorii ssp. caspia in Zambia (PMID:28986641)
• CDC Diagnosis and Management of Tickborne Rickettsial Diseases (PMID:27172113)
• Prevalence of Rickettsia species in ticks in Kazakhstan (PMID:31053085)
• Incidence of SFG Rickettsia in rodents in Kazakhstan (PMID:36050456)
• Astrakhan spotted fever — MONDO:0024473 (Monarch)
• Astrakhan spotted fever — NORD rare disease page

Reference Validation

Checked with linkml-reference-validator 0.3.0rc3.

Quotes not found in the cited source

Searched the abstract, any retrieved full text, and the title. A quote drawn from a part of the paper that was not retrieved will appear here too, so check before treating one as invented:

Every one of these was searched against an abstract alone, with no full text retrieved - marked abstract only below. Where full text can be fetched, re-running with it will settle them; where the source publishes only a summary to PubMed, as GeneReviews chapters do, it will not, and the quote has to be checked by hand against the chapter itself.

• PMID:16223955 (abstract only): "Most of the patients had dogs and reported having contact with Rhipicephalus sanguineus dog ticks"
• closest text in source: "Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established"
• PMID:16223955 (abstract only): "in patients of rural areas"
• Text part not found as substring: 'in patients of rural areas' (note: only abstract available for PMID:16223955, full text may contain this excerpt)
• PMID:16223955 (abstract only): "Most of the patients had dogs and reported having contact with Rhipicephalus sanguineus dog ticks"
• closest text in source: "Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established"
• PMID:16223955 (abstract only): "in patients of rural areas"
• Text part not found as substring: 'in patients of rural areas' (note: only abstract available for PMID:16223955, full text may contain this excerpt)
• PMID:16223955 (abstract only): "the presence of a tache noire was reported in only 23% of the patients"
• Text part not found as substring: 'the presence of a tache noire was reported in only 23% of the patients' (note: only abstract available for PMID:16223955, full text may contain this excerpt)
• PMID:12498120 (abstract only): "Doxycycline efficiency was higher than that of rifampicin"
• closest text in source: "CONCLUSION: Doxicycline efficiency was higher than that of rifampicin"

Quotes that could not be checked

There was no text to compare these against, so they are neither confirmed nor contradicted:

• PMID:1583342: "Astrakhan fever rickettsiae were found to be serologically and antigenically similar to Israeli spotted fever rickettsiae. Both of them probably belong to a single Rickettsia conorii pathotype complex. Only PFGE pattern analysis could clearly discriminate Astrakhan fever rickettsiae from other isolates"
• Reference resolved but exposes no abstract or full text to search
• PMID:1583342: "Astrakhan fever rickettsiae were found to be serologically and antigenically similar to Israeli spotted fever rickettsiae. Both of them probably belong to a single Rickettsia conorii pathotype complex. Only PFGE pattern analysis could clearly discriminate Astrakhan fever rickettsiae from other isolates"
• Reference resolved but exposes no abstract or full text to search

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

• MONDO:0024473 (7 mentions) - the report calls it "Monarch"; MONDO calls it Astrakhan spotted fever
• DOID:0050041 (2 mentions) - the report calls it "DOID"; DOID calls it Astrakhan spotted fever
• NCBITaxon:302011 (3 mentions) - the report calls it "caspia"; NCBITaxon calls it Rickettsia conorii subsp. caspia
• CHEBI:50845 (1 mention) - the report calls it "First line"; CHEBI calls it doxycycline
• CHEBI:28077 (1 mention) - the report calls it "Used in Russian series, less effective than doxycycline"; CHEBI calls it rifampicin
• CHEBI:17698 (1 mention) - the report calls it "Historical alternative for SFG rickettsioses"; CHEBI calls it chloramphenicol

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: GARD.